JavaWeb学习记录总结（二十九）--ServletSessionCookieFilter实现自动登录和记住密码

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JavaWeb学习记录总结（二十九）--ServletSessionCookieFilter实现自动登录和记住密码

一、Servlet

package autologin.servlet.login;

import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.tomcat.util.codec.binary.Base64;

import autologin.domain.Admin;

public class LoginServlet extends HttpServlet {

   public void doGet(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       String oper=request.getParameter("oper");
       if("pre".equals(oper)){
           Cookie autoLoginCookie = getCookie(request);
           if(autoLoginCookie!=null){
               String value=autoLoginCookie.getValue();
               if(!"".equals(value)){
                   String[] values=value.split(":");
                   if(values.length==2){
                       request.setAttribute("auto", 0);
                       request.setAttribute("name", values[0]);
                       request.setAttribute("pass", values[1]);
                   }else if(values.length==3){
                       request.setAttribute("name", values[0]);
                       request.setAttribute("pass", values[1]);
                       request.setAttribute("auto", values[2]);
                   }
               }
           }
           request.getRequestDispatcher("./login.jsp").forward(request, response);
       }else if("login".equals(oper)){
           String name=request.getParameter("name");
           String pass=request.getParameter("pass");
           String[] rpass=request.getParameterValues("rpass");
           String[] alogin=request.getParameterValues("alogin");
           if("zsf".equals(name)&&"123".equals(pass)){
               Admin admin=new Admin(name, pass);
               //存储到session中去
               request.getSession().setAttribute("admin", admin);
               loginCookie(request, response, name, pass, rpass, alogin);
               request.getRequestDispatcher("./index.jsp").forward(request, response);
           }else{
               loginCookie(request, response, name, pass, rpass, alogin);
               //登录失败，重定向
               response.sendRedirect("./login.do?oper=pre");
           }

       }else if("delete".equals(oper)){
           HttpSession session=request.getSession();
           session.removeAttribute("admin");
           request.getRequestDispatcher("./index.jsp").forward(request, response);
       }
   }

   private Cookie getCookie(HttpServletRequest request) {
       Cookie[] cookies=request.getCookies();
       Cookie autoLoginCookie=null;
       if(cookies!=null&&cookies.length>0){
           for(Cookie cookie:cookies){
               String cookieName=cookie.getName();
               if("autologin".equals(cookieName)){
                   autoLoginCookie=cookie;
               }
           }
       }
       return autoLoginCookie;
   }

   private void loginCookie(HttpServletRequest request,
           HttpServletResponse response, String name, String pass,
           String[] rpass, String[] alogin) {
       String value="";
       if(alogin!=null){
           //自动登录操作
           value=name+":"+md5(pass)+":"+1;
       }else if(rpass!=null){
           //记住密码操作
           value=name+":"+md5(pass);
       }
       Cookie autoLoginCookie = getCookie(request);
       if(autoLoginCookie==null){
           autoLoginCookie=new Cookie("autologin", value);
       }else{
           //重新设置值
           autoLoginCookie.setValue(value);
       }
       //加入到响应中
       response.addCookie(autoLoginCookie);
   }

   public void doPost(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException {
       doGet(request, response);
   }

   public String md5(String input){
       try {
           MessageDigest md=MessageDigest.getInstance("md5");
           byte buffer[]=md.digest(input.getBytes());
           byte[] temp=Base64.encodeBase64(buffer);
           System.out.println(new String(temp));
           return new String(temp);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }
}
二、Filter

package autologin.filter;

import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

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.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.tomcat.util.codec.binary.Base64;

import autologin.domain.Admin;

public class AutoLoginFilter implements Filter{

   @Override
   public void destroy() {
       // TODO Auto-generated method stub

   }

   @Override
   public void doFilter(ServletRequest req, ServletResponse res,
           FilterChain chain) throws IOException, ServletException {
       HttpServletRequest request=(HttpServletRequest) req;
       HttpServletResponse response=(HttpServletResponse) res;
       String oper=request.getParameter("oper");
       //判断是否是登录的准备操作，如果不是直接放行
       if(!"pre".equals(oper)){
           chain.doFilter(request, response);
           return;
       }
       //1.获取session中的用户，如果有就不需要登录，如果没有直接放行
       HttpSession session=request.getSession();
       Admin admin=(Admin)session.getAttribute("admin");
       if(admin!=null){
           request.getRequestDispatcher("./index.jsp").forward(request, response);
           return;
       }
       //2.获取Cookie中的auto标志对象，对象为空，则继续执行
       Cookie autoLoginCookie=getCookie(request, "autologin");
       if(autoLoginCookie==null){
           chain.doFilter(request, response);
           return;
       }
       //3.autologin name:pass:auto拆分autologin标志，返回长度如果为2，否则继续执行
       String value=autoLoginCookie.getValue();
       if(value==null||"".equals(value)){
           chain.doFilter(request, response);
           return;
       }
       //4.autologin的长度等于3证明是自动登录操作
       String[] values=value.split(":");
       if(values!=null&&values.length==2){
           chain.doFilter(request, response);
           return;
       }
       if(values.length==3){
           String name=values[0];
           String pass=values[1];
           //5.根据name查找这个用户的密码,pass findById Admin getObjectByName(String name)
           Admin getAdmin=new Admin("zsf","123");
           //根据用户名称查询得到的密码
           String gpass=getAdmin.getPass();
           //6判断查询出的pass与autologin标志的pass是否一样，如果不一样，就登录界面
           if(md5(gpass).equals(pass)){
               //7.如果一样,证明有这个用户，自动登录成功，存储到session中
               session.setAttribute("admin", getAdmin);
               request.getRequestDispatcher("./index.jsp").forward(request, response);
               return;
           }
       }
       chain.doFilter(request, response);
   }

   @Override
   public void init(FilterConfig arg0) throws ServletException {
       // TODO Auto-generated method stub

   }
   private Cookie getCookie(HttpServletRequest request,String name) {
       Cookie[] cookies=request.getCookies();
       Cookie autoLoginCookie=null;
       if(cookies!=null&&cookies.length>0){
           for(Cookie cookie:cookies){
               String cookieName=cookie.getName();
               if(name.equals(cookieName)){
                   autoLoginCookie=cookie;
               }
           }
       }
       return autoLoginCookie;
   }
   //md5加密
   public String md5(String input){
       try {
           //消息摘要加密类对象
           MessageDigest md=MessageDigest.getInstance("md5");
           //加密算法
           byte buffer[]=md.digest(input.getBytes());
           //安装base64进一步处理
           byte[] temp=Base64.encodeBase64(buffer);
           System.out.println(new String(temp));
           return new String(temp);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }
}

三、页面

（1）index.jsp

<body>
<div>
   <h1>首页</h1>
</div>
<c:if test="${admin!=null }">
   <div>
       欢迎${admin.name }登录
       <a href="${pageContext.request.contextPath }/login.do?oper=delete">注销</a>
   </div>
</c:if>
   <c:if test="${admin==null }">
   <div>
       <a href="${pageContext.request.contextPath }/login.do?oper=pre">登录</a>
   </div>
</c:if>

</body>

（2）login.jsp

<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">
   
   <script type="text/javascript">
       window.onload=function(){
           var aloginDom=document.getElementById("alogin");
           var rpassDom=document.getElementById("rpass");
           //自动登录事件
           aloginDom.onclick=function(){
               if(this.checked){ //判断自己是否为真
                   if(!rpassDom.checked){//记住密码是否为真，如果为假就让它设置为真
                       rpassDom.checked=true;
                   }
               }
           };
           //记住密码事件
           rpassDom.onclick=function(){
               if(aloginDom.checked){//首先判断自动登录是否为真
                   this.checked=true;//它永远为真
               }
           };
       };
   </script>
</head>

<body>
<div style="text-align: center;">
    <h3>用户登录</h3>
    <div style="text-align: center;">
       <form action="${pageContext.request.contextPath }/login.do?oper=login" method="post">
           <table cellpadding="0" cellspacing="0" border="1">
               <tr>
                   <td>用户名</td>
                   <td><input type="text" name="name" value="${name }" /></td>
               </tr>
               <tr>
                   <td>密码</td>
                   <td><input type="password" name="pass" value="${pass}"/></td>
               </tr>
               <tr>
                   <td colspan="2">
                   <c:if test="${auto==null }">
                       <input type="checkbox" name="rpass" id="rpass"/>记住密码
                       <input type="checkbox" name="alogin" id="alogin"/>自动登录
                   </c:if>
                   <c:if test="${auto==0 }">
                       <input type="checkbox" name="rpass" id="rpass" checked="checked"/>记住密码
                       <input type="checkbox" name="alogin" id="alogin"/>自动登录
                   </c:if>
                   <c:if test="${auto==1 }">
                       <input type="checkbox" name="rpass" id="rpass" checked="checked"/>记住密码
                       <input type="checkbox" name="alogin" id="alogin" checked="checked"/>自动登录
                   </c:if>
                   </td>
               </tr>
               <tr>
                   <td colspan="2">
                       <table width="100%"><tr>
                           <td align="center"><input type="submit" name="submit" value="登录"/></td>
                           <td align="center"><input type="reset" name="reset" value="重置"/></td>
                       </tr></table>
                   </td>
               </tr>
           </table>
       </form>
    </div>
</div>
</body>
</html>
四、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
<display-name>autologin</display-name>
<filter>
   <filter-name>AutoLoginFilter</filter-name>
   <filter-class>autologin.filter.AutoLoginFilter</filter-class>
</filter>
   <filter-mapping>
   <filter-name>AutoLoginFilter</filter-name>
   <url-pattern>/login.do</url-pattern>
</filter-mapping>
<servlet>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>autologin.servlet.login.LoginServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/login.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
    <welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>

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原文地址：https://www.cnblogs.com/ly-radiata/p/4610970.html

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