HTTP is the way modern applications network. It’s how we exchange data & media. Doing HTTP efficiently makes your stuff load faster and saves bandwidth.

OkHttp is an HTTP client that’s efficient by default:

• HTTP/2 support allows all requests to the same host to share a socket.
• Connection pooling reduces request latency (if HTTP/2 isn’t available).
• Transparent GZIP shrinks download sizes.
• Response caching avoids the network completely for repeat requests.

OkHttp perseveres when the network is troublesome: it will silently recover from common connection problems. If your service has multiple IP addresses OkHttp will attempt alternate addresses if the first connect fails. This is necessary for IPv4+IPv6 and for services hosted in redundant data centers. OkHttp initiates new connections with modern TLS features (SNI, ALPN), and falls back to TLS 1.0 if the handshake fails.

Using OkHttp is easy. Its request/response API is designed with fluent builders and immutability. It supports both synchronous blocking calls and async calls with callbacks.

OkHttp supports Android 2.3 and above. For Java, the minimum requirement is 1.7.

http://square.github.io/okhttp/

GET A URL

This program downloads a URL and print its contents as a string. 

package okhttp3.guide;import java.io.IOException;import okhttp3.OkHttpClient;import okhttp3.Request;import okhttp3.Response;public class GetExample {  OkHttpClient client = new OkHttpClient();  String run(String url) throws IOException {    Request request = new Request.Builder()        .url(url)        .build();    try (Response response = client.newCall(request).execute()) {      return response.body().string();    }  }  public static void main(String[] args) throws IOException {    GetExample example = new GetExample();    String response = example.run("https://raw.github.com/square/okhttp/master/README.md");    System.out.println(response);  }}

 

POST TO A SERVER

This program posts data to a service. 

package okhttp3.guide;import java.io.IOException;import okhttp3.MediaType;import okhttp3.OkHttpClient;import okhttp3.Request;import okhttp3.RequestBody;import okhttp3.Response;public class PostExample {  public static final MediaType JSON      = MediaType.parse("application/json; charset=utf-8");  OkHttpClient client = new OkHttpClient();  String post(String url, String json) throws IOException {    RequestBody body = RequestBody.create(JSON, json);    Request request = new Request.Builder()        .url(url)        .post(body)        .build();    try (Response response = client.newCall(request).execute()) {      return response.body().string();    }  }  String bowlingJson(String player1, String player2) {    return "{'winCondition':'HIGH_SCORE',"        + "'name':'Bowling',"        + "'round':4,"        + "'lastSaved':1367702411696,"        + "'dateStarted':1367702378785,"        + "'players':["        + "{'name':'" + player1 + "','history':[10,8,6,7,8],'color':-13388315,'total':39},"        + "{'name':'" + player2 + "','history':[6,10,5,10,10],'color':-48060,'total':41}"        + "]}";  }  public static void main(String[] args) throws IOException {    PostExample example = new PostExample();    String json = example.bowlingJson("Jesse", "Jake");    String response = example.post("http://www.roundsapp.com/post", json);    System.out.println(response);  }}