130_拦截器

目录

• 概述
• 自定义拦截器
  • 新建web子模块
  • 添加web框架支持
  • 编写web.xml
  • 编写applicationContext.xml
  • 编写Controller
  • Artifacts创建lib
  • 配置Tomcat
  • 测试
  • 编写拦截器
  • applicationContext.xml配置拦截器
  • 测试
• 登录判断验证
  • 编写页面：主页，登录页，首页
  • 编写登录拦截器
  • applicationContext.xml配置登录拦截器

概述

自定义拦截器

新建web子模块

添加web框架支持

编写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">

    <!--注册DispatcherServlet，这个是SpringMVC的核心：请求分发器，前置控制器-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--DispatcherServlet要绑定SpringMVC的配置文件-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <!--启动级别设置为1-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <!--
        在SpringMVC中，/ 和 /*
        /：匹配所有的请求，不会匹配jsp页面
        /*：匹配所有的请求，包括jsp页面
        -->
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <!--编码过滤器-->
    <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>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

编写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
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
    <context:component-scan base-package="com.qing.controller"/>
    <!--让SpringMVC不处理静态资源，如：.css .js .html .mp3 .mp4-->
    <mvc:default-servlet-handler/>
    <!--
    支持MVC注解驱动
    在spring中一般采用@RequestMapping注解来完成映射关系
    要想使@RequestMapping注解生效，必须向上下文中注册DefaultAnnotationHandlerMapping和一个AnnotationMethodHandlerAdapter实例
    这两个实例分别在类和方法级别处理
    而annotation-driven配置帮助我们自动完成上述两个实例的注入
    -->
    <mvc:annotation-driven>
        <!--配置消息转换，解决乱码问题-->
        <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-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <!--前缀和后缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

编写Controller

package com.qing.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {

    @GetMapping("/t1")
    public String test01() {
        System.out.println("TestController-->test01");
        return "OK";
    }
}

Artifacts创建lib

配置Tomcat

测试

​

编写拦截器

package com.qing.config;

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 {

    /*
    return true;放行；
    return false;拦截；
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("==============处理前=================");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("==============处理后=================");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("==============清理=================");
    }
}

applicationContext.xml配置拦截器

<?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
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
    <context:component-scan base-package="com.qing.controller"/>
    <!--让SpringMVC不处理静态资源，如：.css .js .html .mp3 .mp4-->
    <mvc:default-servlet-handler/>
    <!--
    支持MVC注解驱动
    在spring中一般采用@RequestMapping注解来完成映射关系
    要想使@RequestMapping注解生效，必须向上下文中注册DefaultAnnotationHandlerMapping和一个AnnotationMethodHandlerAdapter实例
    这两个实例分别在类和方法级别处理
    而annotation-driven配置帮助我们自动完成上述两个实例的注入
    -->
    <mvc:annotation-driven>
        <!--配置消息转换，解决乱码问题-->
        <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-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <!--前缀和后缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--拦截器配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--包括这个请求下面的所有请求-->
            <mvc:mapping path="/**"/>
            <bean class="com.qing.config.MyInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>
</beans>

测试

登录判断验证

编写页面：主页，登录页，首页

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  <h1><a href="${pageContext.request.contextPath}/toLogin">登录页面</a></h1>
  <h1><a href="${pageContext.request.contextPath}/toMain">首页</a></h1>
  </body>
</html>

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

<h1>登录页面</h1>

<form action="${pageContext.request.contextPath}/login" method="post">
    用户名： <input type="text" name="username"/>
    密码： <input type="password" name="password"/>
    <input type="submit" value="提交"/>
</form>

</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h1>首页</h1>
</body>
</html>

编写登录拦截器

package com.qing.config;

import org.springframework.util.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;

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

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession();
        /*
        放行:
        1.去登录页
        2.登录
        3.已经登录
        拦截：
        其他情况，转发到登录页
         */
        String requestURI = request.getRequestURI();
        if (requestURI.contains("toLogin") || requestURI.contains("login")) {
            return true;
        }
        if (session.getAttribute("userLoginInfo") != null) {
            return true;
        }
        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
        return false;
    }
}

applicationContext.xml配置登录拦截器

<?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
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--自动扫描包，让指定包下的注解生效，由IOC容器统一管理-->
    <context:component-scan base-package="com.qing.controller"/>
    <!--让SpringMVC不处理静态资源，如：.css .js .html .mp3 .mp4-->
    <mvc:default-servlet-handler/>
    <!--
    支持MVC注解驱动
    在spring中一般采用@RequestMapping注解来完成映射关系
    要想使@RequestMapping注解生效，必须向上下文中注册DefaultAnnotationHandlerMapping和一个AnnotationMethodHandlerAdapter实例
    这两个实例分别在类和方法级别处理
    而annotation-driven配置帮助我们自动完成上述两个实例的注入
    -->
    <mvc:annotation-driven>
        <!--配置消息转换，解决乱码问题-->
        <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-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <!--前缀和后缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--拦截器配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--包括这个请求下面的所有请求-->
            <mvc:mapping path="/**"/>
            <bean class="com.qing.config.MyInterceptor"/>
        </mvc:interceptor>
        <mvc:interceptor>
            <!--包括这个请求下面的所有请求-->
            <mvc:mapping path="/**"/>
            <bean class="com.qing.config.LoginInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>
</beans>