OkHttp好处

OkHttp支持HTTP1.x和HTTP2 OkHttp相对于其他HTTP客户端有着明显的优势： HTTP2支持允许对同一主机的所有请求共享套接字 连接池减少了请求延迟（如果HTTP2不可用） 透明GZIP缩小了下载大小 相应缓存可以完全避免网络重复请求 当网络有错误时，它能从常见的连接问题中回复过来 如果你的服务有多个IP地址，如果第一次连接失败，OkHttp将尝试备用地址 OkHttp支持现代TLS功能

OkHttp使用

OkHttp官方文档

Get请求

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请求

public class PostExample {
  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();
    }
  }

  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);
  }
}

实现WebSocket通信客户端

String wsUrl = "ws://" + hostName + ":" + port + "/"
//新建client
OkHttpClient client = new OkHttpClient.Builder().build();
//构造request对象
Request request = new Request.Builder().url(wsUrl).build();
//建立WebSocket连接
WebSocket webSocket = client.newWebSocket(request, new WebSocketListener() {
  @Override
  public void onOpen(WebSocket webSocket, Response response) {
    // 打开链接后回调
    mWebSocket = webSocket;
    System.out.println("client onOpen");
    System.out.println("client request header:" + response.request().headers());
    System.out.println("client response header:" + response.headers());
    System.out.println("client response:" + response);
    //开启消息定时发送
    startTask();
  }
  @Override
  public void onMessage(WebSocket webSocket, String text) {
    // 返回数据回调
    System.out.println("client onMessage");
    System.out.println("message:" + text);
  }
  @Override
  public void onClosing(WebSocket webSocket, int code, String reason) {
    // 正在关闭连接回调
    System.out.println("client onClosing");
    System.out.println("code:" + code + " reason:" + reason);
  }
  @Override
  public void onClosed(WebSocket webSocket, int code, String reason) {
    // 关闭连接后回调
    System.out.println("client onClosed");
    System.out.println("code:" + code + " reason:" + reason);
  }
  @Override
  public void onFailure(WebSocket webSocket, Throwable t, Response response) {
    //出现异常会进入此回调
    System.out.println("client onFailure");
    System.out.println("throwable:" + t);
    System.out.println("response:" + response);
  }
});

// 发送数据
webSocket.send("")