Java服务器--使用POST将推送发送到google Firebase Cloud

import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class FCMClient {
    public static void main(String[] args) {
        try {
            // FCM推送消息的目标URL
            URL url = new URL("https://fcm.googleapis.com/fcm/send");
            
            // 创建HTTP连接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            
            // 设置请求头
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setRequestProperty("Authorization", "Bearer YOUR_FCM_SERVER_KEY");
            
            // 构建推送消息的JSON数据
            String jsonPayload = "{ \"to\": \"DEVICE_TOKEN\", \"data\": { \"message\": \"Hello, World!\" } }";
            
            // 发送推送消息
            conn.setDoOutput(true);
            OutputStream outputStream = conn.getOutputStream();
            outputStream.write(jsonPayload.getBytes("UTF-8"));
            outputStream.flush();
            outputStream.close();
            
            // 获取响应结果
            int responseCode = conn.getResponseCode();
            System.out.println("Response Code: " + responseCode);
            
            conn.disconnect();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}