SSM登陆验证之过滤器实现

日常开发中登陆验证是必不可少的，这里介绍过滤器实现的登陆验证。

第一步：创建一个过滤器

package com.test.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginFilter implements Filter{

   private String dispatchUrl = "";
   private String excludeUrl = "";

   @Override
   public void destroy() {

   }

   @Override
   public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
           throws IOException, ServletException {
       HttpServletRequest request = (HttpServletRequest)arg0;
       HttpServletResponse response =(HttpServletResponse)arg1;
       String servletPath = request.getServletPath();

       HttpSession session = request.getSession();
       Object userObj = session.getAttribute("loginUser");

       /*登陆界面和登陆方法不进行过滤*/
       if(servletPath.equals(dispatchUrl) || servletPath.equals(excludeUrl)){
           arg2.doFilter(arg0, arg1);
       }else{
           if (userObj != null) {
               arg2.doFilter(arg0, arg1);
           }else{
               response.sendRedirect(request.getContextPath()+dispatchUrl);
           }
       }
   }

   @Override
   public void init(FilterConfig arg0) throws ServletException {
       dispatchUrl = arg0.getInitParameter("dispatchUrl");
       excludeUrl = arg0.getInitParameter("excludeUrl");
   }

}

第二步：配置web.xml文件(),在springmvc启动配置后加入以下代码

<filter>
   <filter-name>loginFilter</filter-name>
   <filter-class>com.test.filter.LoginFilter</filter-class>
       <init-param>
           
           <param-name>excludeUrl</param-name>
           <param-value>/login</param-value>
       </init-param>
       <init-param>
           
           <param-name>dispatchUrl</param-name>
       <param-value>/login.jsp</param-value>
   </init-param>
    </filter>
<filter-mapping>
    <filter-name>loginFilter</filter-name>
   <url-pattern>*.jsp</url-pattern>
    </filter-mapping>

第三步：创建登陆页面login.jsp，路径在WebContent目录下

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jstl/core_rt" prefix="c"%>
<c:set var="ctx" value="${pageContext.request.contextPath}"></c:set>
<%
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></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">
</head>
<body>
   <form action="${ctx}/login.do" method="post"><br>
       用户名:<input type="text" name="username" id="username" value=""/><br><br>
       密码:<input type="password" name="password" id="password" value=""/>
       <input type="submit" value="登录">
   </form>
</body>
</html>

第四步：创建LoginController类

package com.test.controller;

import javax.servlet.http.HttpSession;

import org.apache.commons.codec.digest.DigestUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.test.domain.User;
import com.test.service.UserService;
import com.test.vo.Result;

@Controller
public class LoginController {

   @Autowired
   private UserService userService;

   @ResponseBody
   @RequestMapping("login.do")
   public Result login(String userName,String password, HttpSession session) {
       User user = this.userService.findUserByUserName(userName);

       if (user == null) {
           return Result.fail(404, "用户不存在");
       }

       if (!DigestUtils.md5Hex(password).equals(user.getPassword())) {
           return Result.fail(403, "用户密码不正确");
       }

       session.setAttribute("loginUser", user);

       return Result.succeed("/jsp/main.jsp");
   }

   @RequestMapping("logout")
   public String logout(HttpSession session) {
       session.invalidate();
       return "redirect:/login.html";
   }

}
第五步：相同路径下添加一个测试页面index.jsp

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SSM登陆验证之过滤器实现

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