REST Template Using Apache HttpClient

Calling REST web services using Spring’s RestTemplate has been already covered in the other post. Here is a template which can be used out side of Spring. A generalize REST template using Apache’s HttpClient API.

package com.your.package.name;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URISyntaxException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpException;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicHeader;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.protocol.HTTP;

public class RestClient {
	public static final int HTTP_OK = 200;
	public static final String SERVER_URL = "BASE URL OF THE REST SERVER";

	public static String doGet(final String url) throws HttpException,
			IOException, URISyntaxException {

		final HttpClient httpClient = new DefaultHttpClient();
		HttpConnectionParams
				.setConnectionTimeout(httpClient.getParams(), 10000);
		HttpGet httpget = new HttpGet(SERVER_URL + url);
		HttpResponse response = httpClient.execute(httpget);
		HttpEntity entity = response.getEntity();
		InputStream instream = entity.getContent();
		return read(instream);
	}

	public static String doPost(final String url, final String POSTText)
			throws URISyntaxException, HttpException, IOException {

		final HttpClient httpClient = new DefaultHttpClient();
		HttpConnectionParams
				.setConnectionTimeout(httpClient.getParams(), 10000);

		HttpPost httpPost = new HttpPost(SERVER_URL + url);
		StringEntity entity = new StringEntity(POSTText, "UTF-8");
		BasicHeader basicHeader = new BasicHeader(HTTP.CONTENT_TYPE,
				"application/json");
		httpPost.getParams().setBooleanParameter(
				"http.protocol.expect-continue", false);
		entity.setContentType(basicHeader);
		httpPost.setEntity(entity);
		HttpResponse response = httpClient.execute(httpPost);
		InputStream instream = response.getEntity().getContent();
		return read(instream);
	}

	public static boolean doPut(final String url, final String PUTText)
			throws URISyntaxException, HttpException, IOException {
		final HttpClient httpClient = new DefaultHttpClient();
		HttpConnectionParams
				.setConnectionTimeout(httpClient.getParams(), 10000);

		HttpPut httpPut = new HttpPut(SERVER_URL + url);
		httpPut.addHeader("Accept", "application/json");
		httpPut.addHeader("Content-Type", "application/json");
		StringEntity entity = new StringEntity(PUTText, "UTF-8");
		entity.setContentType("application/json");
		httpPut.setEntity(entity);
		HttpResponse response = httpClient.execute(httpPut);
		int statusCode = response.getStatusLine().getStatusCode();
		return statusCode == HTTP_OK ? true : false;
	}

	public static boolean doDelete(final String url) throws HttpException,
			IOException, URISyntaxException {
		final HttpClient httpClient = new DefaultHttpClient();
		HttpConnectionParams
				.setConnectionTimeout(httpClient.getParams(), 10000);

		HttpDelete httpDelete = new HttpDelete(SERVER_URL + url);
		httpDelete.addHeader("Accept",
				"text/html, image/jpeg, *; q=.2, */*; q=.2");
		HttpResponse response = httpClient.execute(httpDelete);
		int statusCode = response.getStatusLine().getStatusCode();
		return statusCode == HTTP_OK ? true : false;
	}

	private static String read(InputStream in) throws IOException {
		StringBuilder sb = new StringBuilder();
		BufferedReader r = new BufferedReader(new InputStreamReader(in), 1000);
		for (String line = r.readLine(); line != null; line = r.readLine()) {
			sb.append(line);
		}
		in.close();
		return sb.toString();
	}
}

And it can be used like

RestClient.doDelete("/registration/" + userToken);
RestClient.doGet("/me/profile?ct=" + userToken);
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5 Responses to REST Template Using Apache HttpClient

  1. deromka says:

    Please note that in a multithreaded environment it you should use only one single instance of final static HttpClient httpClient = new DefaultHttpClient(); in RestClient class and use org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager

    // Create an HttpClient with the ThreadSafeClientConnManager.
    // This connection manager must be used if more than one thread will
    // be using the HttpClient.
    ThreadSafeClientConnManager threadSafeClientConnectionManager = new ThreadSafeClientConnManager();
    threadSafeClientConnectionManager.setMaxTotal(MAX_CONNECTIONS);
    this.httpClient = new DefaultHttpClient(threadSafeClientConnectionManager, params);

  2. Ali Aga says:

    Thank you for sharing. Your post helped me in my project.

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