build.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<project basedir="." name="HttpClientExample" xmlns:ivy="antlib:org.apache.ivy.ant">
  <target name="retrieve">
		<ivy:retrieve />
	</target>
</project>

HttpClientExample.java

package info.bouzuya.http_client;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;

public class HttpClientExample {

  private static final int RESPONSE_BODY_MAX_LENGTH = 100 * 1024;
	private static final String URI = "http://foobar/json";
	private static final boolean DONT_USE_RETRY = true;

	public static void main(String[] args) throws HttpException, IOException {
		Map<String, String> parameters = new HashMap<String, String>();
		parameters.put("name1", "value1");
		parameters.put("name2", "value2");

		sendHttpGet(parameters);
		sendHttpPost(parameters);
	}

	private static void sendHttpPost(Map<String, String> parameters)
			throws IOException, HttpException {
		HttpClient client = new HttpClient();
		PostMethod method = new PostMethod(URI);
		if (DONT_USE_RETRY) {
			method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
					new DefaultHttpMethodRetryHandler(0, false));
		}
		NameValuePair[] pairs = toNameValuePairs(parameters);
		method.addParameters(pairs);
		int code = client.executeMethod(method);
		String body = method.getResponseBodyAsString(RESPONSE_BODY_MAX_LENGTH);
		System.out.println("Response Code: " + Integer.toString(code));
		System.out.println("Response Body: " + body);
	}

	private static void sendHttpGet(Map<String, String> parameters)
			throws IOException, HttpException {
		HttpClient client = new HttpClient();
		GetMethod method = new GetMethod(URI);
		if (DONT_USE_RETRY) {
			method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
					new DefaultHttpMethodRetryHandler(0, false));
		}
		NameValuePair[] pairs = toNameValuePairs(parameters);
		method.setQueryString(pairs);
		int code = client.executeMethod(method);
		String body = method.getResponseBodyAsString(RESPONSE_BODY_MAX_LENGTH);
		System.out.println("Response Code: " + Integer.toString(code));
		System.out.println("Response Body: " + body);
	}

	private static NameValuePair[] toNameValuePairs(
			Map<String, String> parameters) {
		List<NameValuePair> paramsList = new ArrayList<NameValuePair>();
		for (Map.Entry<String, String> entry : parameters.entrySet()) {
			paramsList.add(new NameValuePair(entry.getKey(), entry.getValue()));
		}
		NameValuePair[] paramsArray = paramsList.toArray(new NameValuePair[0]);
		return paramsArray;
	}
}

ivy.xml

<?xml version="1.0" encoding="UTF-8"?>
<ivy-module version="2.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:noNamespaceSchemaLocation="http://ant.apache.org/ivy/schemas/ivy.xsd"
	xmlns:e="http://ant.apache.org/ivy/extra">
	<info organisation="info.bouzuya" module="info.bouzuya.http_client" />
	<dependencies>
		<dependency org="commons-httpclient" name="commons-httpclient"
			rev="3.1" />
	</dependencies>
</ivy-module>