JSP实现用户登录

一 需求

用户名admin，密码admin，登录成功则使用服务器内部转发到login_success.jsp页面，并且提示登录成功的用户名。如果登录失败则请求重定向到login_failure.jsp页面。

 

二代码

1 login.jsp

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

<%

   String path = request.getContextPath();

   String basePath = request.getScheme()+ "://" +request.getServerName()+ ":" +request.getServerPort()+path+ "/" ;

%>

< html >

         < head >

                 <!-- Page title -->

                 < title > imooc  - Login </ title >

                 <!-- End of Page title -->

                 <!-- Libraries -->

                 < link  type = "text/css"  href = "css/login.css"  rel = "stylesheet"  />         

                 < link  type = "text/css"  href = "css/smoothness/jquery-ui-1.7.2.custom.html"  rel = "stylesheet"  />         

                 < script  type = "text/javascript"  src = "js/jquery-1.3.2.min.js" ></ script >

                 < script  type = "text/javascript"  src = "js/easyTooltip.js" ></ script >

                 < script  type = "text/javascript"  src = "js/jquery-ui-1.7.2.custom.min.js" ></ script >

                 <!-- End of Libraries -->         

         </ head >

         < body >

         < div  id = "container" >

                 < div  class = "logo" >

                         < a  href = "#" >< img  src = "assets/logo.png"  alt = ""  /></ a >

                 </ div >

                 < div  id = "box" >

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

                         < p  class = "main" >

                                 < label > 用户名:  </ label >

                                 < input  name = "username"  value = ""  />

                                 < label > 密码:  </ label >

                                 < input  type = "password"  name = "password"  value = "" >        

                         </ p >

                         < p  class = "space" >

                                 < input  type = "submit"  value = "登录"  class = "login"  style =" cursor :  pointer ;" />

                         </ p >

                         </ form >

                 </ div >

         </ div >

         </ body >

</ html >

2 dologin.jsp

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

<%

  String path = request.getContextPath();

  String basePath = request.getScheme()+ "://" +request.getServerName()+ ":" +request.getServerPort()+path+ "/" ;

  String username = "" ;

  String password = "" ;

  request.setCharacterEncoding( "utf-8" ); //防止中文乱码

 

  username = request.getParameter( "username" );

  password = request.getParameter( "password" );

 

   //如果用户和密码都等于admin,则登录成功

   if ( "admin" .equals(username)&& "admin" .equals(password))

  {

     session.setAttribute( "loginUser" , username);

     request.getRequestDispatcher( "login_success.jsp" ).forward(request, response);

    

  }

   else

  {

     response.sendRedirect( "login_failure.jsp" );

  }

%>

3 login_failure.jsp

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

<%

   String path = request.getContextPath();

   String basePath = request.getScheme()+ "://" +request.getServerName()+ ":" +request.getServerPort()+path+ "/" ;

%>

< html >

         < head >

                 <!-- Page title -->

                 < title > imooc  - Login </ title >

                 <!-- End of Page title -->

                 <!-- Libraries -->

                 < link  type = "text/css"  href = "css/login.css"  rel = "stylesheet"  />         

                 < link  type = "text/css"  href = "css/smoothness/jquery-ui-1.7.2.custom.html"  rel = "stylesheet"  />         

                 < script  type = "text/javascript"  src = "js/jquery-1.3.2.min.js" ></ script >

                 < script  type = "text/javascript"  src = "js/easyTooltip.js" ></ script >

                 < script  type = "text/javascript"  src = "js/jquery-ui-1.7.2.custom.min.js" ></ script >

                 <!-- End of Libraries -->         

         </ head >

         < body >

         < div  id = "container" >

                 < div  class = "logo" >

                         < a  href = "#" >< img  src = "assets/logo.png"  alt = ""  /></ a >

                 </ div >

                 < div  id = "box" >

                     登录失败！请检查用户或者密码! < br >

                   < a  href = "login.jsp" > 返回登录 </ a >   

                 </ div >

         </ div >

         </ body >

</ html >

4 login_success.jsp

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

<%

   String path = request.getContextPath();

   String basePath = request.getScheme()+ "://" +request.getServerName()+ ":" +request.getServerPort()+path+ "/" ;

%>

< html >

         < head >

                 <!-- Page title -->

                 < title > imooc  - Login </ title >

                 <!-- End of Page title -->

                  <!-- Libraries -->

                 < link  type = "text/css"  href = "css/login.css"  rel = "stylesheet"  />         

                 < link  type = "text/css"  href = "css/smoothness/jquery-ui-1.7.2.custom.html"  rel = "stylesheet"  />         

                 < script  type = "text/javascript"  src = "js/jquery-1.3.2.min.js" ></ script >

                 < script  type = "text/javascript"  src = "js/easyTooltip.js" ></ script >

                 < script  type = "text/javascript"  src = "js/jquery-ui-1.7.2.custom.min.js" ></ script >

                 <!-- End of Libraries -->         

         </ head >

         < body >

         < div  id = "container" >

                 < div  class = "logo" >

                         < a  href = "#" >< img  src = "assets/logo.png"  alt = ""  /></ a >

                 </ div >

                 < div  id = "box" >

                   <%

                     String loginUser =  "" ;

                      if (session.getAttribute( "loginUser" )!= null )

                     {

                        loginUser = session.getAttribute( "loginUser" ).toString();

                     }

                   %>

                     欢迎您 < font  color = "red" > <%= loginUser %> </ font > ,登录成功！

                 </ div >

         </ div >

         </ body >

</ html >

 

三运行效果