Java Google Cloud Vision API-在POST请求中发送base64编码图像

我正在用谷歌视觉API做一个小项目。我想检测在POST请求中发送给API的base64编码图像的正面。我的代码基于以下谷歌教程：。显然，可以发送base64编码的图像

这是我的密码：

    File File = new File(args[2]);
    String ImageString;

    FileInputStream fileInputStreamReader = new FileInputStream(File);
    byte[] bytes = new byte[(int)File.length()];
    fileInputStreamReader.read(bytes);
    ImageString = Base64.getEncoder().encodeToString(bytes);

    URL serverUrl = new URL(TARGET_URL + API_KEY); //TARGET_URL = "https://vision.googleapis.com/v1/images:annotate?"
    URLConnection urlConnection = serverUrl.openConnection();
    HttpURLConnection httpConnection = (HttpURLConnection)urlConnection;

    httpConnection.setRequestMethod("POST");
    httpConnection.setRequestProperty("Content-Type", "application/json");

    httpConnection.setDoOutput(true);

    BufferedWriter httpRequestBodyWriter = new BufferedWriter(new
            OutputStreamWriter(httpConnection.getOutputStream()));

    httpRequestBodyWriter.write
            ("{\"requests\":  [{ \"features\":  [ {\"type\": \"FACE_DETECTION\""
                    +"}], \"image\": {\"content\": \"" + ImageString + "\"}]}");
    httpRequestBodyWriter.close();

如您所见，我用字符串替换了“content”字段。我只是不知道我做错了什么。

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提前谢谢

你犯了什么错误？看起来你的大括号不平衡，所以你的内容不是一个有效的JSON，它不应该以}}}]}结尾吗？我有一个错误的请求，我忘记了一个“}”。我以为我用JSONLint验证了JSON。现在可以了！非常感谢。