Of Stack

Simple login example of pure JSP implementation

  • 2021-11-10 10:28:54
  • OfStack

This paper describes the simple login method realized by pure JSP. Share it for your reference, as follows:

There are 4 files web. xml, login. jsp, logout. jsp, welcome. jsp

Test environment: Tomcat 6.0. x

Assuming the project name is LoginSample, my directory structure is like this

...\webapps\LoginSample\WEB-INF\web.xml
...\webapps\LoginSample\login.jsp
...\webapps\LoginSample\logout.jsp
...\webapps\LoginSample\welcome.jsp

web. xml source list: 


<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
  <welcome-file-list>
    <welcome-file>welcome.jsp</welcome-file>
  </welcome-file-list>
</web-app>

login. jsp source list: 


<%@ page contentType="text/html;charset=UTF-8" %>
<html>
 <head>
  <title>JSP Simple login instance </title>
 </head>
 <body>
 <h2> Please log in </h2>
 <form method="POST" >
  Login Name: <input type="text" name="Name"><br>
  Login Password: <input type="text" name="Password" ><br>
  <input type="submit" value="Send"><br>
 <form>
 <%
   if (request.getParameter("Name") != null
       && request.getParameter("Password") != null) {
     String Name = request.getParameter("Name");
     String Password = request.getParameter("Password");
     if (Name.equals("a") && Password.equals("a")) {
       session.setAttribute("Login", "OK");
       session.setAttribute("myCount", new Integer(1));
       response.sendRedirect("welcome.jsp");
     }
     else {
       %>
        Login failed : Incorrect username or password ~ 
       <%
     }
   }
%>
 </body>
</html>

logout. jsp source list: 


<%@ page contentType="text/html;charset=UTF-8" %>
<html>
 <%
  session.setAttribute("Login", "");
 %>
 <body>
 <h2> You have logged out </h2>
 </body>
</html>

welcome. jsp source list: 


<%@ page contentType="text/html" pageEncoding="UTF-8" import="java.util.*"%>
<html>
 <body>
 <h2> Welcome page ( Test session)</h2>
 <%
 String Login = (String)session.getAttribute("Login");
 int   nCount=0;
 if (Login != null && Login.equals("OK")) {
   Integer myCount = (Integer)session.getAttribute("myCount");
   if(myCount!=null)
   {
     nCount = myCount.intValue();
     nCount = nCount + 1;
     session.setAttribute("myCount",new Integer(nCount));
   }
   %>
    Login Successful ,myCount=<%=nCount%></br>
   <input type=button value=" Quit " onclick="javascript:location.href='logout.jsp'">
   <%
 }
 else {
%>
   <jsp:forward page="login.jsp"/>
<%
  }
  %>
  </body>
</html>

I hope this article is helpful to everyone's JSP programming.

Related articles: