摘要：整理一個簡單的攔截器模板，放上源碼
攔截器邏輯
1.攔截想跳過登陸的所有請求
2,不攔截要登陸的請求
3.登陸失敗後會跳到自己所在的頁面
文章目錄
實現效果
1網站首頁
2登陸界面
3登陸成功
4登陸失敗.
會彈出登陸失敗的信息，然後重新刷新該頁面
2相關的文件有:
com.how2java.interceptor.LoginInterceptor
package com.how2java.interceptor; //當前文件所在目錄文件目錄
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;
public class LoginInterceptor implements HandlerInterceptor{
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
// TODO Auto-generated method stub
HttpSession httpSession = request.getSession();
String url = request.getRequestURI();
//除了login.jsp是可以公開訪問的，其餘的URL都進行攔截
Object object = httpSession.getAttribute("userName");//獲取session中userName
if(object != null){ //判斷userName是否爲非空，如果爲非空，則表示已登錄，可繼續操作 即將這個請求傳給相應的控制器
return true;
}else{ //如果爲空，則表示未登錄，返回登錄界面 進行登陸
request.setAttribute("msg", "你還有沒有登錄，請先登錄！");
//轉發至登錄頁面
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
}
return false;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
// TODO Auto-generated method stub
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
// TODO Auto-generated method stub
}
}
com.how2java.controller.LoginController
package com.how2java.controller;
import javax.servlet.http.HttpSession;
import javax.swing.*;
import org.springframework.http.HttpRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import java.awt.*;
@Controller
public class LoginController {
@RequestMapping("login.action")
public String login(String userName,String userPass,HttpSession session) {
System.out.println(userName);
System.out.println(userPass);
System.err.println(1);
session.setAttribute("userName",userName);
if(userName.equals("admin") && userPass.equals("123"))
{
return "index";
}
//如果登陸失敗就重新返回登陸頁面
JOptionPane.showMessageDialog(null, "登陸失敗", "alert", JOptionPane.ERROR_MESSAGE);
return "login";
}
}
springMVC.xml
<mvc:interceptors>
<mvc:interceptor >
<mvc:mapping path="/login2"/>
<mvc:exclude-mapping path="/login"/>
<bean class="com.how2java.interceptor.LoginInterceptor"></bean>
</mvc:interceptor>
</mvc:interceptors>
WEB-INF/jsp/index.jsp 登陸成功後的index
<%@ 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>
<span>你已成功進入本系統</span>
</body>
</html>
WEB-INF/jsp/login.jsp
<%--
Created by IntelliJ IDEA.
User: dell
Date: 2019/4/21
Time: 13:51
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<a href="http://localhost:8080/listCategory"> 測試路徑 </a><br>
<a href="http://localhost:8080/index"> 測試攔截器 </a>
</head>
<body>
</body>
</html>
index.jsp 網站的index
<%--
Created by IntelliJ IDEA.
User: dell
Date: 2019/4/21
Time: 13:51
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<a href="http://localhost:8080/listCategory"> 測試路徑 </a><br>
<a href="http://localhost:8080/index"> 測試攔截器 </a>
</head>
<body>
</body>
</html>