SpringMVC初步学习

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

MVC思想

M:模型(dao,service) V:视图(jsp) C:控制器(servlet)

回顾Servlet

环境搭建,pom文件代码

<?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>com.jie</groupId>
    <artifactId>SSMDemo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

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

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</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>
    </dependencies>

</project>

代码

写一个servlet

package servlet;

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

@WebServlet("/hello")
public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1获取参数
        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");
        }
        //2调用业务层
        //3视图转发或重定向
        req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req,resp);
    }

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

test.jsp

<%--
  Created by IntelliJ IDEA.
  User: 郑佳杰
  Date: 2021/4/22
  Time: 14:47
  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>

运行:

MVC框架要做的事情:

搭建MVC环境

创建一个web项目,在web.xml里注册 DispatcherServlet(是springmvc的核心)
编写一个springmvc-servlet配置文件

<?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">

<!--添加 处理映射器-->
    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<!--添加 处理器适配器-->
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
    <!--添加 视图解析器-->
    <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>

在web.xml插入下面语句

<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>

编写一个控制类

package controller;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

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

public class HelloController implements Controller {
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //ModelAndView 模型和视图
        ModelAndView mv = new ModelAndView();

        //封装对象，放在ModelAndView中。Model
        mv.addObject("msg","HelloSpringMVC!");
        //封装要跳转的视图，放在ModelAndView中
        mv.setViewName("hello"); //: /WEB-INF/jsp/hello.jsp
        return mv;
    }
}

注册编写的类

<bean id="/hello" class="controller.HelloController"/>

在idea的项目结构创建文件夹lib并吧jar包导入进去

运行测试

posted @ 2021-04-22 15:50  一个经常掉线的人  阅读(58)  评论(0)    收藏  举报