SpringMVC拦截器
首先添加依赖：
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.3.1.RELEASE</version>
</dependency>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>7.0</version>
<scope>provided</scope>
</dependency>
配置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_3_1.xsd"
version="3.1">
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:spring.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
配置：spring.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:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="com.fitsoft.controller"/>
<!-- 拦截器的注册 -->
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/user/**"/>
<!-- 排除拦截，一般在通配符中有意义 -->
<!--<mvc:exclude-mapping path="/user/search"/>-->
<bean class="com.fitsoft.core.LoginInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/view/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
目录结构大致是这样的：
配置成功之后编写LoginInterceptor拦截器类：
package com.fitsoft.core;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
/**
* @author Joker
* @since 2019/9/14 0014 15:56
*/
public class LoginInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(javax.servlet.http.HttpServletRequest httpServletRequest, javax.servlet.http.HttpServletResponse httpServletResponse, Object o) throws Exception {
String user = (String) httpServletRequest.getSession().getAttribute("user_session");
if(StringUtils.isEmpty(user)){
System.out.println(httpServletRequest.getContextPath());
httpServletResponse.sendRedirect(httpServletRequest.getContextPath()+"/login");
return false;
}
System.out.println("keketip=====preHandler===>");
// return false;//会终止所有请求
return true;
}
@Override
public void postHandle(javax.servlet.http.HttpServletRequest httpServletRequest, javax.servlet.http.HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
System.out.println("keketip=====postHandler===>");
}
@Override
public void afterCompletion(javax.servlet.http.HttpServletRequest httpServletRequest, javax.servlet.http.HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
System.out.println("keketip=====afterHandler===>");
}
}
这里实现HandlerInterceptor接口，主要有三个方法：
preHandle、postHandle 和 afterCompletion
其中preHandle返回true，否则拦截器就失效了，然后在这个方法里处理请求，判断session中的用户是否为空，如果为空则跳转登录界面，不为空则跳转search界面。
login.jsp：
<%--
Created by IntelliJ IDEA.
User: Joker
Date: 2019/9/14 0014
Time: 16:16
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>登录</h1>
<form action="logined" method="post">
<label>用户名</label>
<input name="username" type="text">
<label>密码</label>
<input name="password" type="text">
<button type="submit">登录</button>
</form>
</body>
</html>
这个是登录界面，只有一个form表单也没有样式，做的很简陋
LoginController：
package com.fitsoft.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import javax.servlet.http.HttpSession;
/**
* @author Joker
* @since 2019/9/14 0014 16:20
*/
@Controller
public class LoginController {
@RequestMapping("/login")
public String login(){
return "login";
}
@RequestMapping("/logined")
public String logined(@RequestParam("username") String username,
@RequestParam("password") String password,
HttpSession httpSession){
System.out.println(username);
System.out.println(password);
httpSession.setAttribute("user_session", "6666666");
return "redirect:user/search";
}
}
我们在登录这个方法里面放入session，登录成功之后跳转到search界面，这样我们的拦截器就会发挥作用了，如果有用户登录，则有session，拦截器放行，如果不进行登录，则没有session，直接访问界面会回到login界面。另外还有一个UserController，访问search跳转到search界面：
package com.fitsoft.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpSession;
/**
* @author Joker
* @since 2019/9/14 0014 16:15
*/
@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping("/search")
public String search(HttpSession httpSession){
return "user/search";
}
}
不算难，会用就行。
