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