A Holistic counter in Servlet

In this program we are going to make a such a servlet which will count the number it has been accessed and the number of threads created by the server.

In this example firstly we are going to create one class named as HolisticCounterInServlet. Now declare a variable counter of int with initial value 0, the value of this counter will be different for each servlet and create a Hashtable object. This object will be shared by all the threads in the container. Inside the doGet() method use the method getWriter() method of the response object which will return the PrintWriter object.

The code of the program is given below:


import java.io.*;

import java.io.IOException;

import java.util.*;

import javax.servlet.*;

import javax.servlet.http.*;



public class HolisticCounter extends HttpServlet{

int counter = 0; //separate For Each Servlet

static Hashtable hashTable = new Hashtable(); //Shared by all the threads 



public void doGet(HttpServletRequest request, HttpServletResponse response)

                             
 throws ServletException, IOException {

  response.setContentType("text/html");

  PrintWriter pw = response.getWriter();

  counter++;

  pw.println("This servlet has been accessed" + counter + "times<br>");

  hashTable.put(this,this);

  pw.println("There are currently" + hashTable.size() + "threads<br>");

  }

}

The output of the program is given below:

Current Comments

3 comments so far (post your own) View All Comments Latest 10 Comments:

I tried the example above, but not getting the multiple threads, I opened new browser, still everytime its giving 1 Threads in console only..

Posted by shaily on Thursday, 09.18.08 @ 13:23pm | #80280

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import javax.servlet.*;
import javax.servlet.httpservlet.*;
import java.io.*;

public class Demo extends HttpServlet
{
public void doPost(HttpServletRequest req,HttpServletResponse res)
{
res.setContentType("text/html");
PrintWriter out=res.getWriter();

out.println("This is example of Sevlet using only doPost(): ");
}
}

Posted by Renu on Monday, 05.12.08 @ 11:56am | #59430

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import java.io.*;
import java.io.IOException;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class HolisticCounter extends HttpServlet{
int counter = 0; //separate For Each Servlet
static Hashtable hashTable = new Hashtable(); //Shared by all the threads

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
counter++;
pw.println("This servlet has been accessed" + counter + "times<br>");
hashTable.put(this,this);
pw.println("There are currently" + hashTable.size() + "threads<br>");
}
}

Posted by rajani on Thursday, 08.9.07 @ 17:17pm | #23025

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