Android网络请求之OkHttp

OkHttp是一个第三方类库，用于Android中请求网络。这是一个开源项目,是安卓端最火热的轻量级框架,由移动支付Square公司贡献(该公司还贡献了Picasso和LeakCanary)。用于替代HttpUrlConnection和Apache
HttpClient(android api23 里已移除HttpClient)

OkHttp是一款优秀的HTTP框架，它支持get请求和post请求，支持基于Http的文件上传和下载，支持加载图片，支持下载文件透明的GZIP压缩，支持响应缓存避免重复的网络请求，支持使用连接池来降低响应延迟问题

OkHttpClient client = new OkHttpClient();
String run(String url) throws IOException {
    Request request = new Request.Builder().url(url).build();
    Response response = client.newCall(request).execute();
    if (response.isSuccessful()) {
        return response.body().string();
    } else {
        throw new IOException("Unexpected code " + response);
    }
}

public static final MediaType JSON = MediaType.get("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();
  }
}