Servlet Login and Logout Example using Cookies
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In Servlet Login and Logout Example using Cookies are performed a kind of information that is stored at client side.
Then we can be learned a lot about cookie e.g. how to create cookie, how to delete cookie, how to get cookie etc.
And we can go to create a login and logout example using servlet cookies.
Using these links: login, logout and profile. User can't go to profile page until he/she is logged in. If user is logged out, he need to login again to visit profile.
In this application, we have created following files.
- index.html
- link.html
- login.html
- LoginServlet.java
- LogoutServlet.java
- ProfileServlet.java
- web.xml
<!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Servlet Login Example</title> </head> <body> <h1>Welcome to Login App by Cookie</h1> <a href="login.html">Login</a>| <a href="LogoutServlet">Logout</a>| <a href="ProfileServlet">Profile</a> </body> </html>
<a href="login.html">Login</a> | <a href="LogoutServlet">Logout</a> | <a href="ProfileServlet">Profile</a> <hr>
<form action="LoginServlet" method="post"> Name:<input type="text" name="name"><br> Password:<input type="password" name="password"><br> <input type="submit" value="login"> </form>
package com.javatpoint;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out=response.getWriter();
request.getRequestDispatcher("link.html").include(request, response);
String name=request.getParameter("name");
String password=request.getParameter("password");
if(password.equals("admin123")){
out.print("You are successfully logged in!");
out.print("<br>Welcome, "+name);
Cookie ck=new Cookie("name",name);
response.addCookie(ck);
else{
out.print("sorry, username or password error!");
request.getRequestDispatcher("login.html").include(request, response);
}
out.close();
}
}
package com.javatpoint;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LogoutServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out=response.getWriter();
request.getRequestDispatcher("link.html").include(request, response);
Cookie ck=new Cookie("name","");
ck.setMaxAge(0);
response.addCookie(ck);
out.print("you are successfully logged out!");
}
}
package com.javatpoint;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ProfileServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out=response.getWriter();
request.getRequestDispatcher("link.html").include(request, response);
Cookie ck[]=request.getCookies();
if(ck!=null){
String name=ck[0].getValue();
if(!name.equals("")||name!=null){
out.print("<b>Welcome to Profile</b>");
out.print("<br>Welcome, "+name);
}
}else{
out.print("Please login first");
request.getRequestDispatcher("login.html").include(request, response);
}
out.close();
}
}
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation=
"http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<servlet>
<description></description>
<display-name>LoginServlet</display-name>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.javatpoint.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>ProfileServlet</display-name>
<servlet-name>ProfileServlet</servlet-name>
<servlet-class>com.javatpoint.ProfileServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ProfileServlet</servlet-name>
<url-pattern>/ProfileServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>LogoutServlet</display-name>
<servlet-name>LogoutServlet</servlet-name>
<servlet-class>com.javatpoint.LogoutServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LogoutServlet</servlet-name>
<url-pattern>/LogoutServlet</url-pattern>
</servlet-mapping>
</web-app>
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