SpringMVC

现在时间:2022年4月19日

视频地址:https://www.bilibili.com/video/BV1aE41167Tu

官方文档:https://docs.spring.io/spring-framework/docs/current/reference/html/core.html

SpringMVC整个项目文件:

链接：https://pan.baidu.com/s/1j0awxgre85RDNk4vYvpvBQ 提取码：8jgn

SpringSSM整合文件:

链接：https://pan.baidu.com/s/1P2I9LEFvv-Q3IXgOpipZdA 提取码：yiwf

注意:整合SSM的数据库都是本人服务器docker中的mysql,是直接可以用的,database.properties的数据库也可以换成自己的. 为了后续的读者可以直接使用,我就公开账号密码了. 为了不影响后续读者使用, 请读者不要随意删除和修改数据库中的文件.

项目练习结构:

避坑:

不要用Tomcat10,要用Tomcat 9 ,因为Controller接口和Tomcat10不兼容,接口导入的是javax.servlet下的包,而Tomcat10用的是jakarta.servlet下的包
子项目使用Maven Webaap的模板创建项目,不然每次都必须在项目结构中创建lib包

用模板后webapp/WEB-INF/web.xml不是4.0版本的,应该手动改成4.0版本的(3.0也行)

4.0

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
  

</web-app>

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">


</web-app>

子项目创建后发现名字写错,直接删除重新创建,不要直接改名字. 即使把所有关于子项目的配置文件都改了,也会有神奇的bug(其实就是自己菜,不知道哪少改了)

在每个子项目的maven中添加以下代码,不然target导不出xml文件

<build>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>true</filtering>
        </resource>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>true</filtering>
        </resource>
    </resources>
</build>

用模板创新的项目, index.jsp没有设置字符编码,可能会乱码. 解决办法

删除原来的index.jsp重新创建,或者直接在index.jsp头部添加:
```
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
```
温馨提示:实在找不到那种离奇bug的时候,八成是环境的问题,别挣扎了,重新创建项目,把代码复制过去吧

1. Spring简介

1.1, 什么是MVC

MVC是模型(Model)、视图(View)、控制器(Controller)的简写，是一种软件设计规范。
是将业务逻辑、数据、显示分离的方法来组织代码。
MVC主要作用是降低了视图与业务逻辑间的双向偶合。
MVC不是一种设计模式，MVC是一种架构模式。当然不同的MVC存在差异。

Model（模型）：数据模型，提供要展示的数据，因此包含数据和行为，可以认为是领域模型或JavaBean组件（包含数据和行为），不过现在一般都分离开来：Value Object（数据Dao）和服务层（行为Service）。也就是模型提供了模型数据查询和模型数据的状态更新等功能，包括数据和业务。

View（视图）：负责进行模型的展示，一般就是我们见到的用户界面，客户想看到的东西。

Controller（控制器）：接收用户请求，委托给模型进行处理（状态改变），处理完毕后把返回的模型数据返回给视图，由视图负责展示。也就是说控制器做了个调度员的工作。

最典型的MVC就是JSP + servlet + javabean的模式。

1.2, 什么是SpringMVC

Spring MVC是Spring Framework的一部分，是基于Java实现MVC的轻量级Web框架。

为什么要学习SpringMVC呢?

轻量级，简单易学
高效 , 基于请求响应的MVC框架
与Spring兼容性好，无缝结合
约定优于配置
功能强大：RESTful、数据验证、格式化、本地化、主题等
简洁灵活

1.3, 中心控制器

Spring的web框架围绕DispatcherServlet设计。DispatcherServlet的作用是将请求分发到不同的处理器。从Spring 2.5开始，使用Java 5或者以上版本的用户可以采用基于注解的controller声明方式。

Spring MVC框架像许多其他MVC框架一样, 以请求为驱动 , 围绕一个中心Servlet分派请求及提供其他功能，DispatcherServlet是一个实际的Servlet (它继承自HttpServlet 基类)。

1.3, SpringMVC执行原理

图为SpringMVC的一个较完整的流程图，实线表示SpringMVC框架提供的技术，不需要开发者实现，虚线表示需要开发者实现。

简要分析执行流程

DispatcherServlet表示前置控制器，是整个SpringMVC的控制中心。用户发出请求，DispatcherServlet接收请求并拦截请求。

我们假设请求的url为 : http://localhost:8080/SpringMVC/hello

如上url拆分成三部分：

http://localhost:8080服务器域名

SpringMVC部署在服务器上的web站点

hello表示控制器

通过分析，如上url表示为：请求位于服务器localhost:8080上的SpringMVC站点的hello控制器。
HandlerMapping为处理器映射。DispatcherServlet调用HandlerMapping,HandlerMapping根据请求url查找Handler。
HandlerExecution表示具体的Handler,其主要作用是根据url查找控制器，如上url被查找控制器为：hello。
HandlerExecution将解析后的信息传递给DispatcherServlet,如解析控制器映射等。
HandlerAdapter表示处理器适配器，其按照特定的规则去执行Handler。
Handler让具体的Controller执行。
Controller将具体的执行信息返回给HandlerAdapter,如ModelAndView。
HandlerAdapter将视图逻辑名或模型传递给DispatcherServlet。
DispatcherServlet调用视图解析器(ViewResolver)来解析HandlerAdapter传递的逻辑视图名。
视图解析器将解析的逻辑视图名传给DispatcherServlet。
DispatcherServlet根据视图解析器解析的视图结果，调用具体的视图。
最终视图呈现给用户。

2. Hello Spring MVC(第一个springmvc程序)

2.1 回顾JavaWeb(Servlet)

Maven

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>SpeingMVC-01-Servlet</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>SpeingMVC-01-Servlet Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>
  <dependencies>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.18</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.2</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>SpeingMVC-01-Servlet</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>

    <resources>
      <resource>
        <directory>src/main/resources</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
        </includes>
        <filtering>true</filtering>
      </resource>
      <resource>
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
        </includes>
        <filtering>true</filtering>
      </resource>
    </resources>

  </build>

</project>

Servlet:

package top.hanbing777;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

//实现Servlet接口
public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //取得参数
        String method = req.getParameter("method");
        if (method.equals("add")){
            req.getSession().setAttribute("msg","执行了add方法");
        }
        if (method.equals("delete")){
            req.getSession().setAttribute("msg","执行了delete方法");
        }
        //业务逻辑
        //视图跳转
        req.getRequestDispatcher("/WEB-INF/jsp/hello.jsp").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req,resp);
    }
}

index.jsp

<html>
    <body>
        <h2>Hello World!</h2>
        <%--${pageContext.request.contextPath}  代表当前项目路径--%>
        <form action="${pageContext.request.contextPath}/hello" methom="get">
            user:<input type="text" name="method"> <br>
            <input type="submit">
        </form>
    </body>
</html>

Hello.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Hello</title>
</head>
<body>
    ${msg}
</body>
</html>

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <display-name>Archetype Created Web Application</display-name>
    <servlet>
        <servlet-name>HelloServlet</servlet-name>
        <servlet-class>top.hanbing777.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>
        <url-pattern>/hello</url-pattern>

    </servlet-mapping>
</web-app>

结果:

2.2 第一个SpringMVC程序

maven:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SpringMVC-02-helloMVC</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>SpringMVC-02-helloMVC Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>SpringMVC-02-helloMVC</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

    </build>
</project>

springmvc-servlet.xml(都是固定的):

需要在这里注册Handler,也就是注册HelloController,了解即可,后续都会用扫描包加注解

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>

    <!--视图解析器:DispatcherServlet给他的ModelAndView-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>


    <!--Handler-->
    <bean id="/hello" class="top.hanbing777.HelloController"/>

</beans>

web.xml(固定的):

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <display-name>Archetype Created Web Application</display-name>
    <!--1.注册DispatcherServlet-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--关联一个springmvc的配置文件:【servlet-name】-servlet.xml-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!--启动级别-1-->
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!--/ 匹配所有的请求；（不包括.jsp）-->
    <!--/* 匹配所有的请求；（包括.jsp）-->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

hello.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>hanbing</title>
    </head>
    <body>
        ${msg}
    </body>
</html>

结果:

3. 注解开发

@Controller:代表这是一个控制器
@RequestMapping("/hello") : 设置url路径

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>SpringMVC-03-annotation</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>SpringMVC-03-annotation Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.18</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.2</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>SpringMVC-03-annotation</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>

    <resources>
      <resource>
        <directory>src/main/resources</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
        </includes>
        <filtering>true</filtering>
      </resource>
      <resource>
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
        </includes>
        <filtering>true</filtering>
      </resource>
    </resources>

  </build>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
  <display-name>Archetype Created Web Application</display-name>
  <!--1.注册DispatcherServlet-->
  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!--关联一个springmvc的配置文件:【servlet-name】-servlet.xml-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc-servlet.xml</param-value>
    </init-param>
    <!--启动级别-1-->
    <load-on-startup>1</load-on-startup>
  </servlet>

  <!--/ 匹配所有的请求；（不包括.jsp）-->
  <!--/* 匹配所有的请求；（包括.jsp）-->
  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

</web-app>

springmvc-servlet.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--自动扫描包,让指定下的注释生效.有ioc容器统一管理-->
    <context:component-scan base-package="top.hanbing777.controller"/>
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>


    <!--视图解析器:DispatcherServlet给他的ModelAndView-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>


</beans>

HelloController:

package top.hanbing777.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController{
    @RequestMapping("/hello")
    public String sayHello(Model model){
        model.addAttribute("msg","Hello,SpringMVC");
        return "hello";
    }
}

hello.jsp

<%--
  Created by IntelliJ IDEA.
  User: 韩冰
  Date: 2022/4/10 0010
  Time: 0:05
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>hello</title>
</head>
<body>
${msg}
</body>
</html>

结果:

4. 关于Controller

maven

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SpringMVC-04-controller</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>SpringMVC-04-controller Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>


    <dependencies>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

    </dependencies>

    <build>
        <finalName>SpringMVC-04-controller</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

    </build>
</project>

web.xml:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SpringMVC-04-controller</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>SpringMVC-04-controller Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>


    <dependencies>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

    </dependencies>

    <build>
        <finalName>SpringMVC-04-controller</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

    </build>
</project>

springmvc-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context
                           http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/mvc
                           http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="top.hanbing777.controller"/>
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

from.jsp

<%--
    Created by IntelliJ IDEA.
    User: 韩冰
        Date: 2022/4/11 0011
            Time: 22:18
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>

        <form action="/e/t1" method="post">
            POST:<input type="text" name="name">
            <input type="submit">
        </form>

        <form action="/e/t2" method="get">
            GET:<input type="text" name="name">
            <input type="submit">
        </form>


    </body>
</html>

test.jsp:

<%--
    Created by IntelliJ IDEA.
    User: 韩冰
        Date: 2022/4/10 0010
            Time: 20:22
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>
        ${msg}
    </body>
</html>

hello.jsp:

<%--
    Created by IntelliJ IDEA.
    User: 韩冰
        Date: 2022/4/10 0010
            Time: 20:50
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>
        hello
    </body>
</html>

index.jsp:

<html>
    <body>
        <h2>Hello World!</h2>

        <form action="/addPOST/1/5" method="post">
            <input type="submit">
        </form>

    </body>
</html>

4.1 关于post乱码问题

EncodingController:

package top.hanbing777.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;

@Controller
public class EncodingController {
    /**
     post情况下,中文返回到浏览器时会乱码
     结果:é©å°
     此时,应该在web.xml配置文件中添加过滤器(spring内置的过滤器)
     结果:韩冰
     */
    @PostMapping("/e/t1")
    public String test01(String name, Model model){
        model.addAttribute("msg",name);
        return "test";
    }

    /**
     get情况下,不会乱码
     结果:韩冰
     */
    @GetMapping("/e/t2")
    public String test02(String name, Model model){
        model.addAttribute("msg",name);
        return "test";
    }

}

xml中添加过滤器:

<filter>
    <filter-name>encoding</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>utf-8</param-value>
    </init-param>
</filter>

结果:

4.2 转发和重定向

注意:

转发 : 可以携带参数
重定向 : 不能携带参数,也不能定向到WEB-INF里的内容

redirectAndForward:

package top.hanbing777.controller;


import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@Controller
public class redirectAndForward {

    //return默认就是转发
    @RequestMapping("/rf/t1")
    public String test01(HttpServletRequest request, HttpServletResponse response){

        HttpSession session = request.getSession();
        System.out.println(session);
        return "hello";
    }


    //重定向
    /*注意:重定向不能定向到WEB-INF里的内容
    return "redirect:index.jsp";:文.件[/rf/index.jsp] 未找到
    index.jsp前要加/  return "redirect:/index.jsp";
     */

    @RequestMapping("/rf/t2")
    public String test02(Model model){
        return "redirect:/index.jsp";
    }

}

结果:

转发:

重定向:

4.3 RestFul风格

RestFul的RequestMapping需要添加参数信息,且方法中的参数需要加@PathVariable注解

@RequestMapping("/add2/{a}/{b}")

@PathVariable int a,@PathVariable int b

@GetMapping代表get请求

@PostMapping代表post请求

get请求的时候可以在直接在url后加参数,post只能from表格传递过去,不然会405报错

package top.hanbing777.controller;


import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

@Controller
public class RestFulController {
    //普通模式: http://localhost:8080/add?a=1&b=2
    @RequestMapping("/add1")
    public String test01(int a,int b,Model model){
        int re = a+b;
        model.addAttribute("msg","结果为:"+re);
        return "test";
    }

    //RestFull模式: http://localhost:8080/add2/1/2

    @RequestMapping("/add2/{a}/{b}")
    //@RequestMapping(value = "/add2/{a}/{b}")等价
    public String test02(@PathVariable int a,@PathVariable int b,Model model){
        int re = a+b;
        model.addAttribute("msg","结果为:"+re);
        return "test";
    }

    //RequestMapping中的GET
    @RequestMapping(value = "/add3/{a}/{b}",method = RequestMethod.GET)
    public String test03(@PathVariable int a,@PathVariable int b,Model model){
        int re = a+b;
        model.addAttribute("msg","结果为:"+re);
        return "test";
    }

    @GetMapping("/addGET/{a}/{b}")
    public String testGET(@PathVariable int a,@PathVariable int b,Model model){
        int re = a+b;
        model.addAttribute("msg","结果为:"+re);
        return "test";
    }

    @PostMapping("/addPOST/{a}/{b}")
    public String testPOST(@PathVariable int a,@PathVariable int b,Model model){
        int re = a+b;
        model.addAttribute("msg","结果为:"+re);
        return "test";
    }

}

结果:

get方法:1+2

post:

4.4 参数的类型是一个实体类的时候

User类:

package top.hanbing777.pojo;


import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor

public class User {
    private String name;
    private int age;
    private String sex;
}

UserController:

package top.hanbing777.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import top.hanbing777.pojo.User;

@Controller
@RequestMapping("/user")
public class UserController {



    /**
    参数加上@RequestParam,可以修改前端从前端接收值的参数名
    @RequestParam("username") String name
    http://localhost:8080/user/t1?username=1
    */
    @GetMapping("/t1")
    public String test01(@RequestParam("username") String name, Model model){
        System.out.println("从前端接收的数据"+name);
        model.addAttribute("msg",name);
        return "test";
    }

    /**
     参数传递是一个类,User类
     http://localhost:8080/user/t2?name=%E9%9F%A9%E5%86%B0&age=21&sex=%E7%94%B7
     从浏览器url复制下来中文会乱码,不过不影响
     浏览器输出结果: User(name=韩冰, age=21, sex=男)
     */
    @GetMapping("/t2")
    public String testUser(User user,Model model){
        System.out.println("从前端接收的数据"+user);
        model.addAttribute("msg",user);
        return "test";
    }

}

结果:

5. json

@ResponseBody // 在方法上加上这个就不会走视图解析器,会直接返回一个字符串

或者在类上加上@RestController

需要导入jackson包

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.13.2.2</version>
</dependency>

以及在applicationContext.xml配置JSON乱码问题配置

<!-- JSON乱码问题配置 -->
<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.StringHttpMessageConverter">
            <constructor-arg value="UTF-8"/>
        </bean>
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper">
                <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                    <property name="failOnEmptyBeans" value="false"/>
                </bean>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

maven:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SpringMVC-08-file</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>SpringMVC-08-file Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <!--jackson包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <!--    <dependency>-->
        <!--      <groupId>javax.servlet</groupId>-->
        <!--      <artifactId>servlet-api</artifactId>-->
        <!--      <version>2.5</version>-->
        <!--    </dependency>-->

        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.4</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <!--jackson包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.2.2</version>
        </dependency>


    </dependencies>

    <build>
        <finalName>SpringMVC-08-file</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

    </build>
</project>

applicationContext.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="top.hanbing777.controller"/>
    <mvc:default-servlet-handler/>
    <!-- JSON乱码问题配置 -->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>


    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--文件上传配置-->
    <bean id="multipartResolver"  class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 -->
        <property name="defaultEncoding" value="utf-8"/>
        <!-- 上传文件大小上限，单位为字节（10485760=10M） -->
        <property name="maxUploadSize" value="10485760"/>
        <property name="maxInMemorySize" value="40960"/>
    </bean>

</beans>

springmvc-servlet.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context
                           http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/mvc
                           http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--自动扫描包,让指定下的注释生效.有ioc容器统一管理-->
    <context:component-scan base-package="top.hanbing777.controller"/>
    <mvc:default-servlet-handler/>
    <!-- JSON乱码问题配置 -->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>


    <!--视图解析器:DispatcherServlet给他的ModelAndView-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>


</beans>

User类:

package top.hanbing777.pojo;


import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor

public class User {
    private String name;
    private int age;
    private String sex;
    
}

JsonUtils:

package top.hanbing777.utils;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

import java.text.SimpleDateFormat;

public class JsonUtils {
    public static String getJson(Object object){
        return getJson(object,"yyyy-MM-dd HH:mm:ss");
    }

    public static String getJson(Object object, String dataFormat){
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS,false);
        SimpleDateFormat sdf = new SimpleDateFormat(dataFormat);
        mapper.setDateFormat(sdf);
        try {
            return mapper.writeValueAsString(object);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }
}

UserController:

package top.hanbing777.controller;


import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import top.hanbing777.pojo.User;
import top.hanbing777.utils.JsonUtils;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 类上加上
 @RestController
 类中的每一个方法都就不会走视图解析器,所以也就不用加@ResponseBody了
 */
//@RestController
@Controller
public class UserController {
    /**
     RequestMapping中加上produces = "application/json;charset=utf-8",就可以解决中文乱码问题
     @RequestMapping(value = "/j1",produces = "application/json;charset=utf-8")
     但是比较麻烦,可以在spring配置文件中配置,解决所有json乱码问题
     */
    //RequestMapping中加上produces = "application/json;charset=utf-8",就可以解决中文乱码问题
    //@RequestMapping(value = "/j1",produces = "application/json;charset=utf-8")
    @RequestMapping(value = "/j1")
    @ResponseBody //加上这个就不会走视图解析器,会直接返回一个字符串
    public String json1() throws JsonProcessingException {
        //jackson中有一个ObjectMapper,可以转化成json
        User user = new User("韩冰", 21, "男");
        return user.toString();
    }

    @RequestMapping(value = "/j2")
    @ResponseBody //加上这个就不会走视图解析器,会直接返回一个字符串
    public String json2() throws JsonProcessingException {
        //jackson中有一个ObjectMapper,可以转化成json
        User user = new User("韩冰", 21, "男");
        ObjectMapper objectMapper = new ObjectMapper();
        String str = objectMapper.writeValueAsString(user);
        return str;
    }


    /**
     *传递list
     */
    @RequestMapping("/j3")
    @ResponseBody
    public String json3() throws JsonProcessingException {
        ObjectMapper mapper = new ObjectMapper();
        List list = new ArrayList();
        User user1 = new User("韩冰1", 21, "男");
        User user2 = new User("韩冰2", 21, "男");
        User user3 = new User("韩冰3", 21, "男");
        User user4 = new User("韩冰4", 21, "男");
        User user5 = new User("韩冰5", 21, "男");
        list.add(user1);
        list.add(user2);
        list.add(user3);
        list.add(user4);
        list.add(user5);
        String str = mapper.writeValueAsString(list);
        return str;
    }

    /**
     *传递时间
     * date:Mon Apr 11 23:32:21 CST 2022
     * ObjectMapper会解析成时间戳:1649691141970
     */
    @RequestMapping("/j4")
    @ResponseBody
    public String json4() throws JsonProcessingException {
        ObjectMapper mapper = new ObjectMapper();
        Date date = new Date();

        /**
         * 传统解决办法,
         *SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");
         *System.out.println(sdf.format(date));
         *return mapper.writeValueAsString(sdf.format(date));
         *结果:"2022-04-101 23:36:49"
         */
        //方法二:修改ObjectMapper的配置
        //时间戳模式改为false
        mapper.configure(SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS,false);

        //时间格式
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");

        //配置ObjectMapper时间格式配置
        mapper.setDateFormat(sdf);

        System.out.println(date);
        return mapper.writeValueAsString(date);
    }


    //使用自己写的工具类
    @RequestMapping("/j5")
    @ResponseBody
    public String test05(){
       //return JsonUtils.getJson(new Date(),"yyyy-MM-dd HH:mm:ss");
       return JsonUtils.getJson(new Date());
    }
}

结果:

6. ajax(异步交互,使用jquery实现)

这里的ajax是用jquery实现的,所以需要导入jquery,或者使用jquery的CDN

maven:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SpringMVC-06-ajax</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>SpringMVC-06-ajax Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <!--jackson包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

    </dependencies>

    <build>
        <finalName>SpringMVC-06-ajax</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

    </build>
</project>

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <display-name>Archetype Created Web Application</display-name>

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>

applicationContext.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="top.hanbing777.controller"/>
    <mvc:default-servlet-handler/>
    <!-- JSON乱码问题配置 -->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>


    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

User类:

package top.hanbing777.pojo;


import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private String name;
    private int age;
    private String sex;
}

AjaxController：

package top.hanbing777.controller;


import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import top.hanbing777.pojo.User;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

@RestController
public class AjaxController {
    @RequestMapping("/t1")
    public String test() {
        return "hello";
    }

    @RequestMapping("/a1")
    public void a1(String name, HttpServletResponse response) throws IOException {
        if ("hanbing".equals(name)) {
            response.getWriter().print("true");
        } else {
            response.getWriter().print("false");
        }
    }

    @RequestMapping("/a2")
    public List<User> a2(String name, HttpServletResponse response) throws IOException {
        List<User> users = new ArrayList<>();
        users.add(new User("韩冰1", 21, "男"));
        users.add(new User("韩冰2", 21, "男"));
        users.add(new User("韩冰3", 21, "男"));
        return users;
    }

    @RequestMapping("/a3") //这个不行
    public String a3(String name, HttpServletResponse response) throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        List<User> users = new ArrayList<>();
        users.add(new User("韩冰1", 21, "男"));
        users.add(new User("韩冰2", 21, "男"));
        users.add(new User("韩冰3", 21, "男"));
        String s = mapper.writeValueAsString(users);
        return s;
    }


    @RequestMapping("/a4")
    public String a4(String name, String pwd) {
        String msg = "";
        if (name != null) {
            if ("admin".equals(name))
                msg = "ok";
            else msg = "error";
        }

        if (pwd != null) {
            if ("admin".equals(pwd))
                msg = "ok";
            else msg = "error";
        }
        return msg;
    }

}

getData.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
        <script src="${pageContext.request.contextPath}/statics/js/jquery-3.6.0.js"></script>
        <script>

            $(function () {
                $("#btn").click(function () {
                    $.post("${pageContext.request.contextPath}/a2", function (data) {
                        console.log(data)
                        console.log(data.length)
                        var html = "";
                        for (var i = 0; i < data.length; i++) {
                            html += "<tr>" +
                                "<td>" + data[i].name + "</td>" +
                                "<td>" + data[i].age + "</td>" +
                                "<td>" + data[i].sex + "</td>" +
                                "</tr>"
                        }
                        $("#content").html(html);
                    });
                })
            })
        </script>
    </head>
    <body>
        <input type="button" id="btn" value="获取数据"/>
        <table width="80%" align="center">
            <tr>
                <td>姓名</td>
                <td>年龄</td>
                <td>性别</td>
            </tr>

            <tbody id="content">
                <%--js生成的html添加到这里--%>
            </tbody>
        </table>

    </body>
</html>

index.jsp:

<%--
    Created by IntelliJ IDEA.
    User: 韩冰
        Date: 2022/4/16 0016
            Time: 23:03
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>

        <script src="${pageContext.request.contextPath}/statics/js/jquery-3.6.0.js"></script>

        <script>
            function a() {
                $.post({
                    url: "${pageContext.request.contextPath}/a1",
                    data: {"name": $("#username").val()},
                    success: function (data, status) {
                        alert(data);
                        console.log("data=" + data);
                        console.log("status=" + status);

                    }
                })
            }
        </script>

    </head>
    <body>
        <%--失去焦点时候,发起一个请求(携带信息)到后台--%>
        用户名:<input type="text" id="username" onblur="a()">
    </body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java"%>
<html>
    <head>
        <title>ajax</title>
        <script src="${pageContext.request.contextPath}/statics/js/jquery-3.6.0.js"></script>
        <script>

            function a1(){
                $.post({
                    url:"${pageContext.request.contextPath}/a4",
                    data:{'name':$("#name").val()},
                    success:function (data) {
                        if (data.toString()=='OK'){
                            $("#userInfo").css("color","red"); //颜色变化有问题,只会显示else中的颜色
                        }else {
                            $("#userInfo").css("color","green");
                        }
                        $("#userInfo").html(data);
                    }
                });
            }
            function a2(){
                $.post({
                    url:"${pageContext.request.contextPath}/a4",
                    data:{'pwd':$("#pwd").val()},
                    success:function (data) {
                        if (data.toString()=='OK'){
                            $("#pwdInfo").css("color","red");
                        }else {
                            $("#pwdInfo").css("color","green");
                        }
                        $("#pwdInfo").html(data);
                    }
                });
            }

        </script>
    </head>
    <body>
        <p>
            用户名:<input type="text" id="name" onblur="a1()"/>
            <span id="userInfo"></span>
        </p>
        <p>
            密码:<input type="text" id="pwd" onblur="a2()"/>
            <span id="pwdInfo"></span>
        </p>
    </body>
</html>

http://localhost:8080

http://localhost:8080/getData.jsp

点击获取数据,网页不会刷新,会异步加载出数据

http://localhost:8080/login.jsp

输入正确的后自动弹出ok(颜色这里有问题)

7. 拦截器

拦截器类似于过滤器,都需要在applicationContext.xml中添加配置文件文件

<!--关于拦截器的配置-->
<mvc:interceptors>
    <mvc:interceptor>
        <!--/** 包括路径及其子路径-->
        <!--/admin/* 拦截的是/admin/add等等这种 , /admin/add/user不会被拦截-->
        <!--/admin/** 拦截的是/admin/下的所有-->
        <mvc:mapping path="/**"/>
        <!--bean配置的就是拦截器-->
        <bean class="top.hanbing777.interceptor.MyInterceptor"/>
    </mvc:interceptor>
</mvc:interceptors>

7.1 实现拦截器

maven

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SpringMVC-07-interceptor</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>SpringMVC-07-interceptor Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <!--jackson包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <!--jackson包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.2.2</version>
        </dependency>



    </dependencies>

    <build>
        <finalName>SpringMVC-07-interceptor</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

    </build>
</project>

applicationContext.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="top.hanbing777.controller"/>
    <mvc:default-servlet-handler/>
    <!-- JSON乱码问题配置 -->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>


    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--关于拦截器的配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--/** 包括路径及其子路径-->
            <!--/admin/* 拦截的是/admin/add等等这种 , /admin/add/user不会被拦截-->
            <!--/admin/** 拦截的是/admin/下的所有-->
            <mvc:mapping path="/**"/>
            <!--bean配置的就是拦截器-->
            <bean class="top.hanbing777.interceptor.MyInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean id="loginInterceptor" class="top.hanbing777.interceptor.UserController"/>
        </mvc:interceptor>
    </mvc:interceptors>
</beans>

控制器:

InterceptorController:

package top.hanbing777.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

//测试拦截器的控制器
@Controller
public class InterceptorController {

    @RequestMapping("/interceptor")
    @ResponseBody
    public String testFunction() {
        System.out.println("控制器中的方法执行了");
        return "hello";
    }
}

对应的过滤器:

MyInterceptor

package top.hanbing777.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor {

    //在请求处理的方法之前执行
    //如果返回true执行下一个拦截器
    //如果返回false就不执行下一个拦截器
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("------------处理前------------");
        return true;
    }

    //在请求处理方法执行之后执行
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("------------处理后------------");
    }

    //在dispatcherServlet处理后执行,做清理工作.
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("------------清理------------");
    }
}

注意:

有个问题:

InterceptorController中的方法return出去是一个字符串"hello"因为加了@ResponseBody, 按常理讲页面只会有一个hello, 但是请求/interceptor时会跳转到下一个例子的登录界面, 搞不懂

下面的控制台可能会乱码

在VM options中添加:

-Dfile.encoding=UTF-8

结果:

7.2 实现登录判断逻辑

必须先登录才能看到登录后的首页,没登录想要跳转到登录后的首页,会被拦截器拦截,然后跳转界面. 登录成功后在Session放入一个值, 拦截器判断是否存在该值, 从而实现是否拦截. 登录后注销,就从Session移除这个值.

登录控制器:

LoginInterceptor:

package top.hanbing777.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class LoginInterceptor  {

    @RequestMapping("/toLogin")
    public String toLogin(){
        return "login";
    }

    @RequestMapping("/toMain")
    public String toMain(){
        return "main";
    }

    @RequestMapping("/login")
    public String login(String username, String pwd, HttpSession session, Model model){
        if("admin".equals(username)&&"admin".equals(pwd)){
            model.addAttribute("user",username);
            session.setAttribute("user",username);
            return "main";
        }

        model.addAttribute("msg","账号或密码错误");
        return "login";

    }

    @RequestMapping("/logout")
    public String logout(HttpSession session){
        session.removeAttribute("user");
        return "login";
    }

}

登录拦截器:

UserController

package top.hanbing777.interceptor;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class UserController implements HandlerInterceptor {


    // 如果是登陆页面则放行
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        // 如果是登陆页面则放行
        if (request.getRequestURI().contains("login")) {
            return true;
        }

        // 如果用户已登陆也放行
        HttpSession session = request.getSession();
        if (session.getAttribute("user")!=null) {
            return true;
        }

        // 用户没有登陆跳转到登陆页面
        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
        return false;
    }
}

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>$Title$</title>
    </head>
    <body>
        <h1>这是一个登录前首页</h1>
        <hr>
        <%--登录--%>
        <a href="${pageContext.request.contextPath}/user/toLogin">登录</a>
        <a href="${pageContext.request.contextPath}/user/toMain">首页</a>
    </body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>

    <h1>登录页面</h1>
    <br>
    <a href="${pageContext.request.contextPath}/">返回首页</a>
    <hr>

    <body>
        <form action="${pageContext.request.contextPath}/user/login">
            <span>${msg}</span>
            <br/>
            用户名：<input type="text" name="username"> <br>
            密码：<input type="password" name="pwd"> <br>
            <input type="submit" value="提交">
        </form>
    </body>
</html>

main.jsp

<%--
    Created by IntelliJ IDEA.
    User: 韩冰
        Date: 2022/4/18 0018
            Time: 22:16
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>
        <h1>
            这是一个登录后首页
        </h1>
        你好:${user}
        <br/>

        <a href="${pageContext.request.contextPath}/user/logout">注销</a>

    </body>
</html>

结果：

登录前:

直接点击首页,不会跳转到首页, 会跳转到登录页面

密码错误会弹出提示信息

登录成功后

点击注销跳转到登录界面

8. 文件的上传和下载

maven

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>SpringMVC-08-file</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>SpringMVC-08-file Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <!--jackson包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <!--    <dependency>-->
        <!--      <groupId>javax.servlet</groupId>-->
        <!--      <artifactId>servlet-api</artifactId>-->
        <!--      <version>2.5</version>-->
        <!--    </dependency>-->

        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.4</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>


    </dependencies>

    <build>
        <finalName>SpringMVC-08-file</finalName>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>

        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>

    </build>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <display-name>Archetype Created Web Application</display-name>

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>


    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>


</web-app>

applicationContext.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="top.hanbing777.controller"/>
    <mvc:default-servlet-handler/>
    <!-- JSON乱码问题配置 -->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>


    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--文件上传配置-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 -->
        <property name="defaultEncoding" value="utf-8"/>
        <!-- 上传文件大小上限，单位为字节（10485760=10M） -->
        <property name="maxUploadSize" value="10485760"/>
        <property name="maxInMemorySize" value="40960"/>
    </bean>

</beans>

success.jsp:

<%--
    Created by IntelliJ IDEA.
    User: 韩冰
        Date: 2022/4/18 0018
            Time: 23:53
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>
        成功
    </body>
</html>

index.jsp:

<%--
    Created by IntelliJ IDEA.
    User: 韩冰
        Date: 2022/4/18 0018
            Time: 23:32
                To change this template use File | Settings | File Templates.
                --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>
        1:
        <form action="${pageContext.request.contextPath}/upFile1" enctype="multipart/form-data" method="post">
            <input type="file" name="file"/>
            <input type="submit" value="upload">
        </form>
        2:
        <form action="${pageContext.request.contextPath}/upFile2" enctype="multipart/form-data" method="post">
            <input type="file" name="file"/>
            <input type="submit" value="upload">
        </form>


        <a href="${pageContext.request.contextPath}/download">点击下载</a>

    </body>
</html>

8.1 文件的上传

上传时需要在applicationContext.xml配置,这个是spring提供的,所以这段代码是固定的

<!--文件上传配置-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 -->
    <property name="defaultEncoding" value="utf-8"/>
    <!-- 上传文件大小上限，单位为字节（10485760=10M） -->
    <property name="maxUploadSize" value="10485760"/>
    <property name="maxInMemorySize" value="40960"/>
</bean>

utils包中的getUUID:

获得一个UUID,避免文件重名

package top.hanbing777.utils;

import java.util.UUID;

public class getUUID {
    public static String getID(){
        return UUID.randomUUID().toString().replaceAll("-","");
    }
}

upFile:

两种方法:

upFile1和upFile2

package top.hanbing777.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

import javax.servlet.http.HttpServletRequest;
import java.io.*;

@Controller
public class upFile {
    //@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile 对象
    //批量上传CommonsMultipartFile则为数组即可
    @RequestMapping("/upFile1")
    public String upFile1(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException, IOException {

        //获取文件名 : file.getOriginalFilename();
        String uploadFileName = file.getOriginalFilename();

        //如果文件名为空，直接回到首页！
        if ("".equals(uploadFileName)) {
            return "redirect:/index.jsp";
        }
        System.out.println("上传文件名 : " + uploadFileName);

        //上传路径保存设置
        /**
         request.getServletContext()爆红的话,所以需要引入3.0以上的jar包。
         <groupId>javax.servlet</groupId>
         <artifactId>javax.servlet-api</artifactId>
         <version>3.0.1</version>
         <scope>provided</scope>
         */
        String path = request.getServletContext().getRealPath("/upload");
        //如果路径不存在，创建一个
        File realPath = new File(path);
        if (!realPath.exists()) {
            realPath.mkdir();
        }
        System.out.println("上传文件保存地址：" + realPath);

        //文件名
        String fileName = top.hanbing777.utils.getUUID.getID();
        //文件名后缀
        fileName=fileName+file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf("."));
        file.transferTo(new File(realPath +"/"+ fileName));

        InputStream is = file.getInputStream(); //文件输入流
        OutputStream os = new FileOutputStream(new File(realPath, fileName)); //文件输出流

        //读取写出
        int len = 0;
        byte[] buffer = new byte[1024];
        while ((len = is.read(buffer)) != -1) {
            os.write(buffer, 0, len);
            os.flush();
        }
        os.close();
        is.close();
        return "redirect:/index.jsp";
    }


    /*
     * 采用file.Transto 来保存上传的文件
     */
    @RequestMapping("/upFile2")
    public String  upFile2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {

        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        File realPath = new File(path);
        if (!realPath.exists()){
            realPath.mkdir();
        }
        //上传文件地址
        System.out.println("上传文件保存地址："+realPath);

        //通过CommonsMultipartFile的方法直接写文件（注意这个时候）
        //ile.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));
        //文件名
        String fileName = top.hanbing777.utils.getUUID.getID();
        //文件名后缀
        fileName=fileName+file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf("."));
        file.transferTo(new File(realPath +"/"+ fileName));

        return "redirect:/index.jsp";
    }
}

结果:

已经上传到服务器

8.2 文件下载

downFile

package top.hanbing777.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;

@Controller
public class downFile {
    @RequestMapping(value = "/download")
    public String downloads(HttpServletResponse response, HttpServletRequest request) throws Exception {
        //要下载的图片地址
        String path = request.getServletContext().getRealPath("/upload");
        String fileName = "1e1c7fa2ae9e426a927d1f01937e8446.PNG";

        //1、设置response 响应头
        response.reset(); //设置页面不缓存,清空buffer
        response.setCharacterEncoding("UTF-8"); //字符编码
        response.setContentType("multipart/form-data"); //二进制传输数据
        //设置响应头
        response.setHeader("Content-Disposition",
                "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));

        File file = new File(path, fileName);
        //2、 读取文件--输入流
        InputStream input = new FileInputStream(file);
        //3、 写出文件--输出流
        OutputStream out = response.getOutputStream();

        byte[] buff = new byte[1024];
        int index = 0;
        //4、执行 写出操作
        while ((index = input.read(buff)) != -1) {
            out.write(buff, 0, index);
            out.flush();
        }
        out.close();
        input.close();
        return null;
    }
}

指定一个图片文件:

结果:

posted @ 2022-04-19 22:29 Null777 阅读(230) 评论(0) 收藏举报

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SpringMVC

SpringMVC

1. Spring简介

1.1, 什么是MVC

1.2, 什么是SpringMVC

1.3, 中心控制器

1.3, SpringMVC执行原理

2. Hello Spring MVC(第一个springmvc程序)

2.1 回顾JavaWeb(Servlet)

2.2 第一个SpringMVC程序

3. 注解开发

4. 关于Controller

4.1 关于post乱码问题

4.2 转发和重定向

4.3 RestFul风格

5. json

6. ajax(异步交互,使用jquery实现)

7. 拦截器

7.1 实现拦截器

7.2 实现登录判断逻辑

8. 文件的上传和下载

8.1 文件的上传

8.2 文件下载

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