springMVC的拦截器

小咪咪 2021-10-09 09:48 388阅读 0赞

1.编写login.jsp(页面一定要清理session缓存 不然前端拦截会有上一次的缓存出现 误导拦截效果)

<%@ page language="java" contentType="text/html; charset=UTF-8"  
    pageEncoding="UTF-8"%>  
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">  
<html>  
<head>  
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
<title>Insert title here</title>  
</head>  
<body>  
  
<form action="$\{pageContext.request.contextPath \}/login.action" method="post">  
  
<%@ page language="java" %>       
<%       
 session.invalidate();       
%>     
<label>账号：</label>  
<br>  
<input type="text" name="username">  
<br>  
<label>密码：</label>  
<br>  
<input type="password" name="password">  
<br>  
<input type="submit" value="确定">  
  
</form>  
  
</body>  
</html>

2.编写拦截器Interceptor.class

package com.itheima.springmvc.interceptor;  
  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import javax.servlet.http.HttpSession;  
  
import org.springframework.web.servlet.HandlerInterceptor;  
import org.springframework.web.servlet.ModelAndView;  
  
import com.itheima.springmvc.pojo.User;  
  
public class interceptor implements HandlerInterceptor \{  
  
    public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)  
            throws Exception \{  
        // TODO Auto-generated method stub  
  
    \}  
  
    public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)  
            throws Exception \{  
        // TODO Auto-generated method stub  
  
    \}  
//判断用户是否登录  
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object obj) throws Exception \{  
      
        String requestURI = request.getRequestURI();  
  
        if(!requestURI.contains("/login.action")&&!requestURI.contains("/toLogin.action"))\{//放行/login.action和/toLogin.action  
                String username = (String) request.getSession().getAttribute("username");  
                if(username =="")\{//判断空字符串的方式 username != null 这种方式是错的  
                                response.sendRedirect(request.getContextPath()+"/toLogin.action");//如果为空跳转到登录页面  
                               return false;  
                \}  
            \}  
            return true;  
    \}

\}  
3.在springMVC.xml中配置拦截器

<mvc:interceptors>  
<mvc:interceptor>  
<mvc:mapping path="/\*\*"/>  
<bean class="com.itheima.springmvc.interceptor.interceptor"></bean>  
</mvc:interceptor>  
</mvc:interceptors>

4.编写controller层

@RequestMapping("toLogin.action")  
        public String login()\{  
            return "login";  
        \}  
        @RequestMapping("login.action")  
        public String login(  
                String username,  
                String password,  
                HttpSession httpSession)\{  
                httpSession.setAttribute("username", username);  
              
            return "redirect:/item/itemlist.action";  
        \}