public class LoggingInterceptor implements Interceptor {
public Response intercept(Chain chain) throws IOException {
 Request request = chain.request();

 long t1 = System.nanoTime();
 System.out.println(String.format("发送请求: [%s] %s%n%s",
   request.url(), chain.connection(), request.headers()));

 Response response = chain.proceed(request);

 long t2 = System.nanoTime();
 System.out.println(String.format("接收响应: [%s] %.1fms%n%s",
   response.request().url(), (t2 - t1) / 1e6d, response.headers()));

 return response;
}
}

client.interceptors().add(new LoggingInterceptor()); //添加应用拦截器
client.networkInterceptors().add(new LoggingInterceptor()); //添加网络拦截器

public class ApiClient {
 Interceptor signedRequestInterceptor = new Interceptor() {
  @Override
  public Response intercept(Chain chain) throws IOException {
   Response response = null;
   try {
    Request originalRequest = chain.request();
    Request signedRequest = SignRequestUtil.signRequest(originalRequest);
    response = chain.proceed(signedRequest);
   } catch (NoSuchAlgorithmException | InvalidKeyException e) {
     e.printStackTrace();
   }

   return response;
  }
 };

 OkHttpClient client = new OkHttpClient();
 client.networkInterceptors().add(signedRequestInterceptor);
}
public class SignRequestUtil {
 public static Request signRequest(Request originalRequest) {
  Request.Builder requestBuilder = originalRequest.newBuilder();

  // 在这做所有你需要做的事情，重新产生一个 Request 送出去。
  return requestBuilder
   .headers(getSignedHeaders(originalRequest))
   .build();
 }
}