How to add,set and get Header in request of HttpClient?

In my application I need to set the header in the request and I need to print the header value in the console... So please give an example to do this the HttpClient or edit this in my code...

My Code is ,

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

public class SimpleHttpPut { 
  public static void main(String[] args) {
    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost("http://http://localhost:8089/CustomerChatSwing/JoinAction");
    try {
      List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
      nameValuePairs.add(new BasicNameValuePair("userId",
      "123456789"));
      post.setEntity(new UrlEncodedFormEntity(nameValuePairs));

      HttpResponse response = client.execute(post);
      BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
      String line = "";
      while ((line = rd.readLine()) != null) {
    System.out.println(line);
      }

    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}  

Thanks in advance...