Java是一種廣泛應用的編程語言，支持各種方式的網絡通信。在Web應用中，REST（Representational State Transfer）是一種常見的API設計方式。RESTful API接口可以使用HTTP REST協議與客戶端進行通信。POST方法是常用RESTful API接口操作之一，并且對于JSON格式數據朝峰良好的支持。下面介紹如何使用Java的POST方法發送RESTful API接口請求。

public static void main(String[] args) {
try {
URL url = new URL("http://example.com/api/resource");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "application/json");
String data = "{\"name\": \"John\", \"age\": 30}";
OutputStream outputStream = connection.getOutputStream();
outputStream.write(data.getBytes());
outputStream.flush();
outputStream.close();
int responseCode = connection.getResponseCode();
System.out.println("Response Code : " + responseCode);
BufferedReader in = new BufferedReader(
new InputStreamReader(connection.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
System.out.println(response.toString());
} catch (Exception e) {
System.out.println("Exception Occurred: " + e.getMessage());
}
}

以上代碼使用Java的HttpURLConnection類來構建POST請求并發送請求。需要設置Connection的請求方法為“POST”，然后設置輸出流來傳輸JSON數據。在POST請求發送之后，需要解析返回的HTTP狀態碼和響應數據。