JSP的Cookie在登录中的应用

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一 功能需求

实现记忆用户名和密码功能。

 

二 代码

1、login.jsp

<%@  page  language = "java"  import = "java.util.*, java.net .*"  contentType = "text/html; charset=utf-8" %>

<%

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 'index.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" >

        

   head >

 

   < body >

     < h1 > 用户登录 h1 >

     < hr >

     <%

      request.setCharacterEncoding( "utf-8" );

      String username= "" ;

      String password =  "" ;

      Cookie[] cookies = request.getCookies();

       if (cookies!= null &&cookies.length>0)

      {

            for (Cookie c:cookies)

           {

               if (c.getName().equals( "username" ))

              {

                   username =  URLDecoder.decode(c.getValue(), "utf-8" );

              }

               if (c.getName().equals( "password" ))

              {

                   password =  URLDecoder.decode(c.getValue(), "utf-8" );

              }

           }

      }

     %>

     < form  name = "loginForm"  action = "dologin.jsp"  method = "post" >

        < table >

          < tr >

            < td > 用户名： td >

            < td >< input  type = "text"  name = "username"  value = " <%= username  %> " /> td >

          tr >

          < tr >

            < td > 密码： td >

            < td >< input  type = "password"  name = "password"  value = " <%= password  %> "  /> td >

          tr >

          < tr >

            < td  colspan = "2" >< input  type = "checkbox"  name = "isUseCookie"  checked = "checked" /> 十天内记住我的登录状态 td >

          tr >

          < tr >

            < td  colspan = "2"  align = "center" >< input  type = "submit"  value = "登录" />< input  type = "reset"  value = "取消" /> td >

          tr >

        table >

     form >

   body >

html >

2、dologin.jsp

<%@   page   language = "java"   import = "java.util.*, java.net .*"   contentType = "text/html; charset=utf-8" %>

<%

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 'dologin.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" >

        

 

   head >

 

   < body >

     < h1 > 登录成功 h1 >

     < hr >

     < br >

     < br >

     < br >

     <%

       request.setCharacterEncoding( "utf-8" );

        //首先判断用户是否选择了记住登录状态

       String[] isUseCookies = request.getParameterValues( "isUseCookie" );

        if (isUseCookies!= null &&isUseCookies.length>0)

       {

           //把用户名和密码保存在Cookie对象里面

          String username = URLEncoder.encode(request.getParameter( "username" ), "utf-8" );

           //使用URLEncoder解决无法在Cookie当中保存中文字符串问题

          String password = URLEncoder.encode(request.getParameter( "password" ), "utf-8" );

         

          Cookie usernameCookie =  new  Cookie( "username" ,username);

          Cookie passwordCookie =  new  Cookie( "password" ,password);

          usernameCookie.setMaxAge(864000);

          passwordCookie.setMaxAge(864000); //设置最大生存期限为10天

          response.addCookie(usernameCookie);

          response.addCookie(passwordCookie);

       }

        else

       {

          Cookie[] cookies = request.getCookies();

           if (cookies!= null &&cookies.length>0)

          {

              for (Cookie c:cookies)

             {

                 if (c.getName().equals( "username" )||c.getName().equals( "password" ))

                {

                    c.setMaxAge(0);  //设置Cookie失效

                    response.addCookie(c);  //重新保存。

                }

             }

          }

       }

     %>

     < a  href = "users.jsp"  target = "_blank" > 查看用户信息 a >

   

   body >

 

html >

3、users.jsp

<%@  page  language = "java"  import = "java.util.*, java.net .*"  contentType = "text/html; charset=utf-8" %>

<%

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 'users.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" >

        

 

   head >

 

   < body >

     < h1 > 用户信息 h1 >

     < hr >

     <%

      request.setCharacterEncoding( "utf-8" );

      String username= "" ;

      String password =  "" ;

      Cookie[] cookies = request.getCookies();

       if (cookies!= null &&cookies.length>0)

      {

            for (Cookie c:cookies)

           {

               if (c.getName().equals( "username" ))

              {

                   username = URLDecoder.decode(c.getValue(), "utf-8" );

              }

               if (c.getName().equals( "password" ))

              {

                   password = URLDecoder.decode(c.getValue(), "utf-8" );

              }

           }

      }

     %>

     < BR >

     < BR >

     < BR >

         用户名： <%= username  %> < br >

         密码： <%= password  %> < br >

   body >

html >

 

三 测试

 

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