sending http post (httpclient 4.x - httpcomponents) with parameters example

a_post_httpclient_sample.java

List<NameValuePair> formparams = new ArrayList<NameValuePair>();
formparams.add(new BasicNameValuePair("param1", "value1"));
formparams.add(new BasicNameValuePair("param2", "value2"));
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams, "UTF-8");
HttpPost httppost = new HttpPost("http://localhost/handler.do");
httppost.setEntity(entity);

ClientFormLogin.java

package org.apache.http.examples.client;

import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.cookie.Cookie;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

/**
 * A example that demonstrates how HttpClient APIs can be used to perform
 * form-based logon.
 */
public class ClientFormLogin {

    public static void main(String[] args) throws Exception {

        DefaultHttpClient httpclient = new DefaultHttpClient();
        try {
            HttpGet httpget = new HttpGet("https://portal.sun.com/portal/dt");

            HttpResponse response = httpclient.execute(httpget);
            HttpEntity entity = response.getEntity();

            System.out.println("Login form get: " + response.getStatusLine());
            EntityUtils.consume(entity);

            System.out.println("Initial set of cookies:");
            List<Cookie> cookies = httpclient.getCookieStore().getCookies();
            if (cookies.isEmpty()) {
                System.out.println("None");
            } else {
                for (int i = 0; i < cookies.size(); i++) {
                    System.out.println("- " + cookies.get(i).toString());
                }
            }

            HttpPost httpost = new HttpPost("https://portal.sun.com/amserver/UI/Login?" +
                    "org=self_registered_users&" +
                    "goto=/portal/dt&" +
                    "gotoOnFail=/portal/dt?error=true");

            List <NameValuePair> nvps = new ArrayList <NameValuePair>();
            nvps.add(new BasicNameValuePair("IDToken1", "username"));
            nvps.add(new BasicNameValuePair("IDToken2", "password"));

            httpost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));

            response = httpclient.execute(httpost);
            entity = response.getEntity();

            System.out.println("Login form get: " + response.getStatusLine());
            EntityUtils.consume(entity);

            System.out.println("Post logon cookies:");
            cookies = httpclient.getCookieStore().getCookies();
            if (cookies.isEmpty()) {
                System.out.println("None");
            } else {
                for (int i = 0; i < cookies.size(); i++) {
                    System.out.println("- " + cookies.get(i).toString());
                }
            }

        } finally {
            // When HttpClient instance is no longer needed,
            // shut down the connection manager to ensure
            // immediate deallocation of all system resources
            httpclient.getConnectionManager().shutdown();
        }
    }
}

other examples,
http://www.vogella.de/articles/ApacheHttpClient/article.html

The Commons HttpClient project is now end of life, and is no longer being developed. It has been replaced by the Apache HttpComponents project in its HttpClient and HttpCore modules, which offer better performance and more flexibility.

http://hc.apache.org/httpclient-legacy/index.html