用JSP实现WEB页面登录验证

1.index.html

系统登录

2.login.jsp

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








<%
 String user_name= request.getParameter("uid");
 String pass_word = request.getParameter("upwd");
 if(user_name!=null && !user_name.equals("")){
 
 try{
             Class.forName("org.gjt.mm.mysql.Driver");
             Connection conn=DriverManager.getConnection("jdbc:mysql://localhost/test","test","test");
             Statement stmt=(Statement)conn.createStatement();
             String sql="select * from account where username='"+user_name+"'";
             sql +="and password='"+pass_word+"'";
             ResultSet rs=(ResultSet)stmt.executeQuery(sql);
             if(rs.next())
                  {
                  session.setAttribute("login","ok");
                  session.setAttribute("uname",user_name);
%>
  
  <%                    
               
               }else out.println("错误的用户名和密码");
                  out.println("返回");
           }catch(Exception ee){ee.printStackTrace();}
          
    }else{
             out.println("请先登录");
             out.println("返回"); 
          }      
       
       




 %>





3.main.jsp


<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>








<%@include file="checkvalid.jsp"%>
欢迎进入本页面，您已经通过了验证，你的用户名是:<%=session.getAttribute("uname") %>

 
您可以跳转到后续页面
 




4.checkvalid.jsp


<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>








<%
  if(session.getAttribute("login")==null||!session.getAttribute("login").equals("ok"))
  {response.sendRedirect("index.html");}

 %>



5.continue.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>







<%@include file="checkvalid.jsp"%>
<%=session.getAttribute("uname") %>,欢迎您进入第二个页面！