springMVC-拦截器
1 基本环境搭建
1.1 创建普通maven项目,添加web支持
1.2 配置web.xml
1.3 配置springmvc配置文件 applicationContext.xml
1.4 创建控制层和拦截器层的两个包
2 简单测试拦截器
2.1 在拦截器层创建一个拦截器类
package com.lv.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; 执行下一个拦截器,放行
//return false; 不执行下一个拦截器
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("=======处理前=======");
return false;
}
//日志
@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=======");
}
}2.2 在springmvc配置文件中配置拦截器
<!--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.lv.config.MyInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>2.3 在控制层新建一个Controller
package com.lv.controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class TestController {
@GetMapping("/t1")
public String test(){
System.out.println("TestController==>test()方法执行了");
return "OK";
}
}2.4 启动Tomcat测试
2.5 查看后台输出
3 拦截器实现登录验证
3.1 编写index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<h1><a href="${pageContext.request.contextPath}/user/goLogin">登录页面</a></h1>
<h1><a href="${pageContext.request.contextPath}/user/main">首页</a></h1>
</body>
</html>3.2 编写登录页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<%--在WEB-INF目录下的所有页面或资源,只能通过controller,或者servlet进行访问--%>
<h1>登录页面</h1>
<form action="${pageContext.request.contextPath}/user/login" method="post">
用户名:<input type="text" name="username" required/>
密码:<input type="text" name="password" required/>
<input type="submit">
</form>
</body>
</html>3.3 编写首页
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<h1>首页</h1>
<span>${username}</span>
<p>
<a href="${pageContext.request.contextPath}/user/goOut">注销</a>
</p>
</body>
</html>3.4 创建一个Controller
package com.lv.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 LoginController {
@RequestMapping("/goLogin")
public String login(){
return "login";
}
@RequestMapping("/login")
public String login(HttpSession session, String username, String password, Model model){
//把用户的信息存在session中
session.setAttribute("userLoginInfo",username);
model.addAttribute("username",username);
return "main";
}
@RequestMapping("/main")
public String main(){
return "main";
}
@RequestMapping("/goOut")
public String goOut(HttpSession session){
session.removeAttribute("userLoginInfo");
return "login";
}
}3.5 编写用户登录拦截器
package com.lv.config;
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: 判断什么情况下登录
//登录页面会放行
if (request.getRequestURI().contains("goLogin")){
return true;
}
//提交登录放行
if (request.getRequestURI().contains("login")){
return true;
}
//已经登录成功放行
if (session.getAttribute("userLoginInfo") != null){
return true;
}
//没有登录的情况
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
return false;
}
}3.6 在springmvc配置文件中配置拦截器
<!--拦截器配置-->
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/user/**"/>
<bean class="com.lv.config.LoginInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>3.7 启动Tomcat测试
