原问题已经回答，仅供路过谷歌的人参考；这是一个更完整的示例，如何使用 Arduino 将数据发布到网络服务器:

The original question is already answered, but just for reference for people passing by via Google; here is a more complete example how to post data to a webserver with an Arduino:

IPAddress server(10,0,0,138);
String PostData = "someDataToPost";

if (client.connect(server, 80)) {
  client.println("POST /Api/AddParking/3 HTTP/1.1");
  client.println("Host: 10.0.0.138");
  client.println("User-Agent: Arduino/1.0");
  client.println("Connection: close");
  client.print("Content-Length: ");
  client.println(PostData.length());
  client.println();
  client.println(PostData);
}