Firebase Cloud Message 通过 HTTP v1 api 使用主题函数返回 400

我试图用 fcm 测试主题函数。

这是错误消息这是我的请求 json

这是我的服务器代码

 @Override
    public void sendTopic(TopicRequestVo requestVo) throws IOException {
            Gson gs = new Gson();
            GoogleTopicRequestVo googlereqVo = new GoogleTopicRequestVo();
            Payload payload = requestVo.getPayload();
            //读取token
            InputStream inputStream = new ClassPathResource("/static/server-account.json").getInputStream();
            GoogleCredential googleCredential = GoogleCredential
                    .fromStream(inputStream)
                    .createScoped(Arrays.asList("https://www.googleapis.com/auth/firebase.messaging"));
            if (googleCredential.refreshToken()) {
                System.out.println("refresh success");
            }
            System.out.println("refresh fail");
            System.out.println(googleCredential.getAccessToken());
            //设置通知消息
            googlereqVo.setNotification(new NotificationInfo(payload.getTitle(),payload.getBody()));
            //设置数据消息
    //        Map<String, String> data = requestVo.getData();
    //        googlereqVo.setData(data);
            googlereqVo.setTopic(requestVo.getTopic());
            GoogleV2RequestVo req = new GoogleV2RequestVo();
            req.setMessage(googlereqVo);
            try {
                HttpURLConnection conn = getConnection(Constant.API_URL_TOPIC_FCM, googleCredential.getAccessToken());
                OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream(), StandardCharsets.UTF_8);
                String s = gs.toJson(req);
                System.out.println(s);
                wr.write(s);
                wr.flush();
                BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
                String line = null;
                while ((line = reader.readLine()) != null) {
                    System.out.println(line);
                }
                wr.close();
                reader.close();
            } catch (Exception e) {
                e.printStackTrace();
            }


     //API_URL_TOPIC_FCM = "https://fcm.googleapis.com/v1/projects/rlpushmsgdemo/messages:send HTTP/1.1";
     private HttpURLConnection getConnection(String path,String accesstoken)throws IOException{
            URL url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setUseCaches(false);
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestProperty("Authorization", "Bearer " + accesstoken);
            conn.setRequestProperty("Content-Type", "application/json;charset=UTF-8");
            return conn;
        }

我正在用谷歌的指南做类似的代码，我不知道哪里错了，它几乎困扰了我 1 小时，谁能告诉我原因，在此先感谢。