SpringMVC拦截器实现登录认证

package com.mvc.action; 
 
import javax.servlet.http.HttpSession; 
 
import org.springframework.stereotype.Controller; 
import org.springframework.web.bind.annotation.RequestMapping; 
 
/** 
 * 登录认证的控制器 
 */ 
@Controller 
public class LoginControl { 
 
 /** 
  * 登录 
  * @param session 
  *   HttpSession 
  * @param username 
  *   用户名 
  * @param password 
  *   密码 
  * @return 
  */ 
 @RequestMapping(value="/login") 
 public String login(HttpSession session,String username,String password) throws Exception{  
  //在Session里保存信息 
  session.setAttribute("username", username); 
  //重定向 
  return "redirect:hello.action"; 
 } 
  
 /** 
  * 退出系统 
  * @param session 
  *   Session 
  * @return 
  * @throws Exception 
  */ 
 @RequestMapping(value="/logout") 
 public String logout(HttpSession session) throws Exception{ 
  //清除Session 
  session.invalidate(); 
   
  return "redirect:hello.action"; 
 } 
  
  
  
} 

package com.mvc.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; 
/** 
 * 登录认证的拦截器 
 */ 
public class LoginInterceptor implements HandlerInterceptor{ 
 
 /** 
  * Handler执行完成之后调用这个方法 
  */ 
 public void afterCompletion(HttpServletRequest request, 
   HttpServletResponse response, Object handler, Exception exc) 
   throws Exception { 
   
 } 
 
 /** 
  * Handler执行之后，ModelAndView返回之前调用这个方法 
  */ 
 public void postHandle(HttpServletRequest request, HttpServletResponse response, 
   Object handler, ModelAndView modelAndView) throws Exception { 
 } 
 
 /** 
  * Handler执行之前调用这个方法 
  */ 
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, 
   Object handler) throws Exception { 
  //获取请求的URL 
  String url = request.getRequestURI(); 
  //URL:login.jsp是公开的;这个demo是除了login.jsp是可以公开访问的，其它的URL都进行拦截控制 
  if(url.indexOf("login.action")>=0){ 
   return true; 
  } 
  //获取Session 
  HttpSession session = request.getSession(); 
  String username = (String)session.getAttribute("username"); 
   
  if(username != null){ 
   return true; 
  } 
  //不符合条件的，跳转到登录界面 
  request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response); 
   
  return false; 
 } 
 
} 

<?xml version="1.0" encoding="UTF-8"?> 
<beans xmlns="http://www.springframework.org/schema/beans" 
 xmlns:aop="http://www.springframework.org/schema/aop" 
 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-4.0.xsd 
  http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd 
  http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd 
  http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd"> 
   
  <!-- 使用组件扫描 --> 
  <!-- 将action扫描出来，在spring容器中进行注册，自动对action在spring容器中进行配置 --> 
  <context:component-scan base-package="com.mvc.action" /> 
   
  <!-- 项目的Handler 
  <bean name="/hello.action" class="com.mvc.action.HelloAction"></bean> 
   --> 
  <!-- 处理器映射器HandlerMapping --> 
  <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/> 
   
  <!-- 处理器设配器HandlerAdapter --> 
  <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"> 
   <property name="messageConverters"> 
    <list> 
     <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean> 
    </list> 
   </property> 
  </bean> 
 
  <!-- 视图解析器ViewResolver --> 
  <!-- 解析jsp,默认支持jstl --> 
  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> 
   <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"></property> 
   <property name="prefix" value="/WEB-INF/jsp/" /> 
   <property name="suffix" value=".jsp" /> 
  </bean> 
   
  <!-- 在实际开发中通常都需配置 mvc:annotation-driven标签,这个标签是开启注解 --> 
  <mvc:annotation-driven></mvc:annotation-driven> 
  <!-- 拦截器 --> 
  <mvc:interceptors> 
   <!-- 多个拦截器，顺序执行 --> 
   <mvc:interceptor> 
    <mvc:mapping path="/**"/> 
    <bean class="com.mvc.interceptor.LoginInterceptor"></bean> 
   </mvc:interceptor> 
  </mvc:interceptors> 
  
</beans> 

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> 
<% 
String path = request.getContextPath(); 
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 
%> 
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 
<html> 
 <head> 
 <base href="<%=basePath%>"> 
  
 <title>My JSP 'login.jsp' starting page</title> 
  
 <meta http-equiv="pragma" content="no-cache"> 
 <meta http-equiv="cache-control" content="no-cache"> 
 <meta http-equiv="expires" content="0">  
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 
 <meta http-equiv="description" content="This is my page"> 
 <!-- 
 <link rel="stylesheet" type="text/css" href="styles.css"> 
 --> 
 
 </head> 
 
 <body> 
  <form action="${pageContext.request.contextPath}/login.action" method="post"> 
  用户名:<input type="text" name="username" /><br> 
  密码:<input type="text" name="password" /><br> 
  <input type="submit" value="登录" /> 
  </form> 
 </body> 
</html> 

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 
<%@taglib uri="http://www.springframework.org/tags" prefix="spring" %> 
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form" %> 
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> 
<% 
String path = request.getContextPath(); 
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 
%> 
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 
<html> 
 <head> 
 <base href="<%=basePath%>"> 
  
 <title>My JSP 'hello.jsp' starting page</title> 
  
 <meta http-equiv="pragma" content="no-cache"> 
 <meta http-equiv="cache-control" content="no-cache"> 
 <meta http-equiv="expires" content="0">  
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 
 <meta http-equiv="description" content="This is my page"> 
 <!-- 
 <link rel="stylesheet" type="text/css" href="styles.css"> 
 --> 
 
 </head> 
 
 <body> 
 当前用户:${username} 
 <c:if test="${username!=null}"> 
  <a href="${pageContext.request.contextPath }/logout.action">退出</a> 
 </c:if> 
 ${message} 
 </body> 
</html> 

package com.mvc.action; 
 
import org.springframework.stereotype.Controller; 
import org.springframework.ui.Model; 
import org.springframework.web.bind.annotation.RequestMapping; 
 
//标记这个类是一个Handler处理器 
@Controller 
public class HelloAction{ 
 
 @RequestMapping("/hello")//制定这个控制类对应的url 
 public String hello(Model model){ 
  String message = "SpringMVC"; 
  //为model添加Attribute 
  model.addAttribute("message",message); 
  return "hello"; 
 } 
// public ModelAndView handleRequest(HttpServletRequest request, 
//   HttpServletResponse response) throws Exception { 
//  
//  //在页面上提示一行信息 
//  String message = "hello world!"; 
//  
//  //通过request对象将信息在页面上展示 
//  //request.setAttribute("message", message); 
//  
//  ModelAndView modelAndView = new ModelAndView(); 
//  // 相当于request.setAttribute(), 将数据传到页面展示 
//  //model数据 
//  modelAndView.addObject("message", message); 
//  //设置视图 
//  modelAndView.setViewName("hello"); 
//  
//  return modelAndView; 
// } 
  
  
 
  
}