官方用一句话进行了介绍：
An HTTP & HTTP/2 client for Android and Java applications.
一、概述
HTTP 是互联网上应用最为广泛的一种网络协议，可用于传输数据和媒体
高效使用HTTP不仅让内容加载更快，且节省带宽
对HTTP 不熟可以看之前的一篇文章：HTTP，请求消息，响应消息，Cookie（详细总结）
OkHttp是从设计之初就是一款高效的 HTTP client
HTTP/2允许同一host的所有请求共享socket连接池降低了请求延迟 (if
HTTP/2isn’t available)GZIP缩减了下载的大小响应缓存完全避免网络重复请求
OkHttp会确保网络的连接，它会悄悄地恢复一些常见的连接问题如果你的 service 有多个IP地址且第一个连接失败，OkHttp将尝试备用地址。
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.
OkHttp 的易用性
Its request/response API is designed with fluent builders and immutability.
它同时支持同步阻塞调用和回调的异步调用
OkHttp支持Android 2.3及以上。对于Java，最低要求是1.7
二、使用例子
1. GET A URL
下面这个程序下载一个URL，并以字符串打印出其内容：
// 关键代码
OkHttpClient client = new OkHttpClient();
String run(String url) throws IOException {
Request request = new Request.Builder()
.url(url)
.build();
Response response = client.newCall(request).execute();
return response.body().string();
}
// 完整代码
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();
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);
}
}
2. POST TO A SERVER
提交数据到服务端
// 关键代码
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();
Response response = client.newCall(request).execute();
return response.body().string();
}
// 完整代码
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();
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);
}
}
三、ja包下载或引用
<dependency>
<groupId>com.squareup.okhttp3</groupId>
<artifactId>okhttp</artifactId>
<version>3.2.0</version>
</dependency>
- GRADLE
compile 'com.squareup.okhttp3:okhttp:3.2.0'
参考文章：
[1] 官方原文：OkHttp
