public class Headers {
  public static void main(String[] args) throws IOException {
  OkHttpClient client = new OkHttpClient();

  Request request = new Request.Builder()
      .url("http://www.baidu.com")
      .header("User-Agent", "My super agent")
      .addHeader("Accept", "text/html")
      .build();

  Response response = client.newCall(request).execute();
  if (!response.isSuccessful()) {
    throw new IOException("服务器端错误: " + response);
  }

  System.out.println(response.header("Server"));
  System.out.println(response.headers("Set-Cookie"));
  }
}

 private final OkHttpClient client = new OkHttpClient();

 public void run() throws Exception {
  Request request = new Request.Builder()
    .url("http://publicobject.com/helloworld.txt")
    .build();

  Response response = client.newCall(request).execute();
  if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

  Headers responseHeaders = response.headers();
  for (int i = 0; i < responseHeaders.size(); i++) {
   System.out.println(responseHeaders.name(i) + ": " + responseHeaders.value(i));
  }

  System.out.println(response.body().string());
 }

private final OkHttpClient client = new OkHttpClient();

 public void run() throws Exception {
  Request request = new Request.Builder()
    .url("http://publicobject.com/helloworld.txt")
    .build();

  client.newCall(request).enqueue(new Callback() {
   @Override public void onFailure(Request request, IOException throwable) {
    throwable.printStackTrace();
   }

   @Override public void onResponse(Response response) throws IOException {
    if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

    Headers responseHeaders = response.headers();
    for (int i = 0; i < responseHeaders.size(); i++) {
     System.out.println(responseHeaders.name(i) + ": " + responseHeaders.value(i));
    }

    System.out.println(response.body().string());
   }
  });
 }