servlet和Cookie实现记住账号密码功能

Posted 2021-03-03 yorkzhangyang

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篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了servlet和Cookie实现记住账号密码功能相关的知识，希望对你有一定的参考价值。

1.实现jQuery异步登录

https://www.cnblogs.com/YorkZhangYang/p/12539726.html

2.jQuery获取checkbox选项组的值

https://www.cnblogs.com/YorkZhangYang/p/12587155.html

2.1在1和2的基础上，Login.jsp页面按钮提交事件submitBtn.onclick=function(){}中增加以下代码

 //获取checkbox是否已选中
 let chkbox = $("input[name=‘remember‘]:checkbox").prop("checked");

2.2在$.ajax({}）方法data属性中做以下改变，将checkbox是否选中状态的true和false值提交到servlet

data:{username:strName,password:strPwd,validateCode:strCode,chkbox:chkbox}

3.在servlet类中做如下改变

（1）获取前端传过来的checkbox是否选中的状态值。

String chkbox = request.getParameter("chkbox");

如果用户名，密码，验证码都正确（登录成功），在将用户名，密码存入session对象的代码后增加以下代码：

（2）验证获取checkbox的checked状态值等于true(已勾选“记住我”选项),则创建cookie对象，并将用户名和密码存入cookie对象，并保存到客户端。

（3）若获取checkbox的checked状态值等于false（未勾选“记住我”选项），则遍历客户端的cookie对象，找到名为用户名和密码的cookie对象，将时效赋值为0(相当于删除已经保存的用户名和密码)。

//将用户名和密码存储到cookie对象
            if(chkbox!=null&&!chkbox.isEmpty()&&chkbox.equals("true")) 
            {
                Cookie cookie1 = new Cookie("username", name);
                Cookie cookie2 = new Cookie("password", pwd);
                //设置cookie的时效
                cookie1.setMaxAge(60*60*24*7);
                cookie2.setMaxAge(60*60*24*7);
                //保存到客户端
                response.addCookie(cookie1);
                response.addCookie(cookie2);
            }
            else //设置原来保存的cookie时效为0（相当于删除Cookie）
            {
                Cookie [] cookies = request.getCookies();
                 //寻找是否已经存在之前保存过的cookie
                for (Cookie cookie:cookies) {
                  if (cookie.getName().equals("username")) {
                    cookie.setMaxAge(0);
                    response.addCookie(cookie);
                  } 
                  if (cookie.getName().equals("password")) {
                    cookie.setMaxAge(0);
                    response.addCookie(cookie);
                  }
                }
            }

4.Login.jsp页面提取保存到客户端的cookie对象，将用户名和密码作为input文本表单的默认value值显示。

<%
String username = "";
String password = "";
Cookie[] cookies = request.getCookies();
if(cookies!=null&&cookies.length>0)
{
    for(Cookie c:cookies)
    {
        if(c.getName().equals("username"))
        {
            username = c.getValue();
        }
        if(c.getName().equals("password"))
        {
            password = c.getValue();
        }
    }
}
out.print(username);
%>

5.完整代码

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录界面</title>
    <!-- Bootstrap -->
     <link href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" rel="stylesheet">
 <script src="js/jquery-1.11.1.min.js"></script>
<style>

    .bg{
        height: 600px;
        background-image:url(images/bg.jpg);
        background-size:cover;
    }

    .form{
        padding: 40px;
       margin-top: 175px;
       background: rgba(255,255,255,0.2);
    }

   .footer{
    height: 60px;
    padding-top:20px; 
    font-size: 14px;
    font-weight: bold;
    text-align: center;
   }
   

   
</style>
</head>
<body>
<%
String username = "";
String password = "";
Cookie[] cookies = request.getCookies();
if(cookies!=null&&cookies.length>0)
{
    for(Cookie c:cookies)
    {
        if(c.getName().equals("username"))
        {
            username = c.getValue();
        }
        if(c.getName().equals("password"))
        {
            password = c.getValue();
        }
    }
}
out.print(username);
%>
    <div class="page-header">
        <h1>XXXX信息系统登录界面</h1>
      </div>
      <div class="container-fluid">
        <div class="row bg">
          <div class="col-md-offset-6 col-md-4 col-sm-offset-3 col-sm-7 col-xs-offset-2 col-xs-8 col-lg-offset-6 col-lg-3 form">
            <form class="form-horizontal" id="loginForm" action="${pageContext.request.contextPath}/LoginServlet" method="post">
                <div class="form-group">
                  <label for="username" class="col-sm-4 control-label">用户名</label>
                  <div class="col-sm-8">
                    <input type="text" class="form-control" id="username" name="username"  value="<%=username %>" placeholder="请输入用户名" onblur="validateusername();">
                  </div>
                </div>
                <div class="form-group">
                  <label for="password" class="col-sm-4 control-label">密码</label>
                  <div class="col-sm-8">
                    <input type="password" class="form-control" id="password" name="password" value="<%=password %>" placeholder="请输入密码" >
                  </div>
                </div>
                <div class="form-group">
                    <label for="validateCode" class="col-sm-4 control-label">验证码</label>
                    <div class="col-sm-4">
                      <input type="text" class="form-control" id="validateCode" name="validateCode" placeholder="请输入验证码">
                    </div>
                    <div class="col-sm-4">
                        <img id="verifyCode" src="${pageContext.request.contextPath}/VerifyCodeImg" alt="Loading" width="75px" height="35px" onclick="changeCode()">
                      </div>
                  </div>
                <div class="form-group">
                  <div class="col-sm-offset-2 col-sm-10">
                    <div class="checkbox">
                      <label>
                        <input type="checkbox" name="remember" value="selected">记住我
                      </label>
                    </div>
                  </div>
                </div>
                <div class="form-group">
                  <div class="col-sm-offset-2 col-sm-10">
                     <button type="button" id="submitBtn" class="btn btn-success" style="width: 50%;" >登录</button>
                  </div>
                </div>
              </form>
                <span style="color: red;" id="tip"></span>
          </div> 
        </div>

        <div class="footer">
                <p>&copy;版权所有：XXXXX学院南宁市仙葫大道XXX号</p>  
                <p>邮编：530001联系邮箱：xxxxxxx@163.com</p> 
        </div>
      </div>

      <script type="text/javascript">
      function changeCode() {
          var codeImg=document.getElementById("verifyCode");
          //这里URL后追加随机数，使程序每次访问的都是不同的资源，防止浏览器缓存，即产生不同的验证码
          codeImg.src="/LoginTest/VerifyCodeImg?d="+Math.random();
      }
      
      
      //首先获取表单的Input对象
      let username = document.getElementById("username");
      let password = document.getElementById("password");
      let validateCode = document.getElementById("validateCode");
      let span = document.getElementById("tip");
      let submitBtn = document.getElementById("submitBtn");
      console.log(validateCode);
     

      password.onblur = function()
      {
        validatepassword();
      }
      
      validateCode.onblur = function()
      {
        validatecode();
      }

      function validateusername()
      {
         let value = username.value;
         if(!value)
         {
            span.innerHTML="用户名不能为空";
            return false;
         }
         else if(value.length<2||value.length>11)
         {
          span.innerHTML="用户名的长度2-12位";
            return false;
         }
         else{
          span.innerHTML="";
            return true;
         }

      }

      function validatepassword()
      {
         let value = password.value;
         if(!value)
         {
            span.innerHTML="密码不能为空";
            return false;
         }
         else if(value.length<2||value.length>11)
         {
          span.innerHTML="密码的长度2-12位";
            return false;
         }
         else{
            span.innerHTML="";
            return true;
         }

      }

      function validatecode()
      {
         let value = validateCode.value;
         if(!value)
         {
            span.innerHTML="验证码不能为空";
            return false;
         }
         
         else{
          span.innerHTML="";
            return true;
         }

      }

     submitBtn.onclick=function(){
       if(validateusername()&&validatepassword()&&validatecode())
       {
        //document.getElementById("loginForm").submit();
           let strName = username.value;
           let strPwd = $("#password").val();
           let strCode = validateCode.value;
           //获取checkbox是否已选中
           let chkbox = $("input[name=‘remember‘]:checkbox").prop("checked");
           
           console.log(strName);
           console.log(strPwd);
           console.log(strCode);
           $.ajax({
             url:"${pageContext.request.contextPath}/LoginServlet",//LoginTest/LoginServlet
             type:"post",
             dataType:"text",
             data:{username:strName,password:strPwd,validateCode:strCode,chkbox:chkbox},
             beforeSend:function(){
                  $("#tip").html("登录中.......");
             },
             success:function(data){  //是从servlet传回来的
               if(data=="ok")
                {
                   $("#tip").html("登录成功！");
                   window.location.href="adminindex.jsp";
                }
               else if(data=="namepwdstr")
                   {
                   $("#tip").html("用户名或密码有错！");                
                   }
               else if(data=="codestr")
                   {
                   $("#tip").html("验证码有错！");   
                   }
             
             },
             error:function()
             {
               $("#tip").html("登录失败！");
             }
             
           
           });
        
        
        
       }
       else
       {
        span.innerHTML="表单为空或不符合要求";
        return false;
       }
     
     }


    </script>   
      
      
     

       <!-- jQuery (Bootstrap 的所有 JavaScript 插件都依赖 jQuery，所以必须放在前边) -->
       <script src="https://cdn.jsdelivr.net/npm/jquery@1.12.4/dist/jquery.min.js"></script>
       <!-- 加载 Bootstrap 的所有 JavaScript 插件。你也可以根据需要只加载单个插件。 -->
       <script src="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js"></script>
</body>
</html>

View Code

LoginServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.websocket.Session;

/**
 * Servlet implementation class LoginServlet
 */
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
        //1.设置获取表单字符集
        request.setCharacterEncoding("utf-8");
        
        //2.设置响应的类型
        //response.setContentType("text/html;charset=UTF-8");
        
        String name = request.getParameter("username");
        String pwd = request.getParameter("password");
        String code = request.getParameter("validateCode");
        String chkbox = request.getParameter("chkbox");
        
        String str="";
        PrintWriter out = response.getWriter();
        
        if(name.equals("")||name==null||pwd.equals("")||pwd==null||code.equals("")||code==null)
        {
            out.print("表单不能为空");
            return;
        }
        //将前端页面获取的验证码转换为小写
        String codelower = code.toLowerCase();
        boolean IsName =name.equals("admin"); 
        boolean IsPwd = pwd.equals("123");
        boolean IsCode = codelower.equals(request.getSession().getAttribute("code").toString().toLowerCase());
                
        if(IsName&&IsPwd&&IsCode)
        {
            request.getSession().setAttribute("username", name);
            request.getSession().setAttribute("password", pwd);
            //response.sendRedirect("adminindex.jsp");
            
            //将用户名和密码存储到cookie对象
            if(chkbox!=null&&!chkbox.isEmpty()&&chkbox.equals("true")) 
            {
                Cookie cookie1 = new Cookie("username", name);
                Cookie cookie2 = new Cookie("password", pwd);
                //设置cookie的时效
                cookie1.setMaxAge(60*60*24*7);
                cookie2.setMaxAge(60*60*24*7);
                //保存到客户端
                response.addCookie(cookie1);
                response.addCookie(cookie2);
            }
            else //设置原来保存的cookie时效为0（相当于删除Cookie）
            {
                Cookie [] cookies = request.getCookies();
                 //寻找是否已经存在之前保存过的cookie
                for (Cookie cookie:cookies) {
                  if (cookie.getName().equals("username")) {
                    cookie.setMaxAge(0);
                    response.addCookie(cookie);
                  } 
                  if (cookie.getName().equals("password")) {
                    cookie.setMaxAge(0);
                    response.addCookie(cookie);
                  }
                }
            }
            str = "ok";
            out.print(str);
            
        }
        else
        {
            if(!IsName||!IsPwd)
            {
                str = "namepwdstr";
                out.print(str);
            }
            if(!IsCode)
            {
                str = "codestr";
                out.print(str);
            }
            //response.sendRedirect("Login.jsp");
        }
        
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

View Code

6.演示效果

技术图片

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