Your own Cookie!

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In this post we will see how to create a simple web app which uses cookies to hold the user data (remember, in http ever request is a new request and cookie is a way to store the user data for subsequent requests to the server).

Refer Cookies in Servlet for information about cookies

Setup tomcat on your machine. (I have used apache-tomcat-8.0.15)
I am using eclipse for installation. Create a dynamic web project, Cookies

My final project structure looks like this:



How to deploy our war file in tomcat.
Export project -> as WAR file -> save it as Cookies in the webapps folder of tomcat.
Start tomcat using startup.bat in bin folder.
Access http://localhost:8080/Cookies/

Create an index.html file:

<form action="servlet1" method="post">
Name : <input type="text" name="name">
<input type="submit" value="Go">
</form>


Create FirstServlet.java class.

package com.cookie.servlets;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FirstServlet extends HttpServlet {

@Override
public void doPost(HttpServletRequest request, HttpServletResponse response) {
try {
String name = request.getParameter("name");

response.setContentType("text/html");

PrintWriter out = response.getWriter();
Cookie c = new Cookie("name", name);
response.addCookie(c);
out.write("Hello " + name);
out.print("<form action='servlet2' method='post'>");  
   out.print("<input type='submit' value='go'>");  
   out.print("</form>");
   out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}


Your web.xml file:

<web-app>

 <servlet>
<servlet-name>servlet1</servlet-name>
<servlet-class>com.cookie.servlets.FirstServlet</servlet-class>
</servlet>

 <servlet-mapping>
<servlet-name>servlet1</servlet-name>
<url-pattern>/servlet1</url-pattern>
</servlet-mapping>

 </web-app>


<-- You can deploy and check at this point -->

Next we create our next servlet, SecondServlet.java


package com.cookie.servlets;

 import java.io.PrintWriter;

 import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

 public class SecondServlet extends HttpServlet{

 @Override
public void doPost(HttpServletRequest request, HttpServletResponse response){
try{
response.setContentType("text/html"); 
PrintWriter out = response.getWriter();  
     
   Cookie ck[]=request.getCookies();  
   out.print("Hello "+ck[0].getValue());  
 
   out.close();  
}catch(Exception e){
e.printStackTrace();
}
}


}

Add the following to web.xml

<servlet>
<servlet-name>servlet2</servlet-name>
<servlet-class>com.cookie.servlets.SecondServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>servlet2</servlet-name>
<url-pattern>/servlet2</url-pattern>
</servlet-mapping>

Your final web.xml looks like this:

<web-app>

<servlet>
<servlet-name>servlet1</servlet-name>
<servlet-class>com.cookie.servlets.FirstServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>servlet1</servlet-name>
<url-pattern>/servlet1</url-pattern>
</servlet-mapping>


<servlet>
<servlet-name>servlet2</servlet-name>
<servlet-class>com.cookie.servlets.SecondServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>servlet2</servlet-name>
<url-pattern>/servlet2</url-pattern>
</servlet-mapping>

</web-app>


Deploy and run.





Use cookie.setMaxAge(0) to delete the cookie information.

Refer Cookies in Servlet for information about cookies


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