java - IBM Watson Q and A API 给出 ​​500 响应代码

Question

我编写了一段 Java 代码来测试 Watson Question and Answers API。但是，当我运行它时，我收到响应代码 500。我已经检查了 api url 和我的登录凭据。问题似乎出在其他地方。任何提示或调试建议都会有很大帮助。

    String url = "https://watson-wdc01.ihost.com/instance/526/deepqa/v1/question";
    URL obj = new URL(url);
    HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();

    //add reuqest header
    String userCredentials = "username:password";
    String basicAuth = "Basic " + DatatypeConverter.printBase64Binary(userCredentials.getBytes());
    con.setRequestProperty ("Authorization", basicAuth);
    con.setRequestProperty("X-SyncTimeout", "30");
    con.setRequestProperty("Accept", "application/json");
    con.setRequestProperty("Content-Type", "application/json");
    con.setRequestProperty("Cache-Control", "no-cache");
    con.setRequestMethod("POST");

    String query = "{\"question\": {\"questionText\": \"" + "What are the common respiratory diseases?" + "\"}}";
    System.out.println(query);

    // Send post request
    con.setDoOutput(true);
    DataOutputStream wr = new DataOutputStream(con.getOutputStream());
    wr.writeBytes(query);
    wr.flush();
    wr.close();

    int responseCode = con.getResponseCode();
    System.out.println("Response Code : " + responseCode);
    BufferedReader in = new BufferedReader(
            new InputStreamReader(con.getInputStream()));
    String inputLine;
    StringBuffer response = new StringBuffer();

    while ((inputLine = in.readLine()) != null) {
        response.append(inputLine);
    }
    in.close();

    //print result
    System.out.println(response.toString());

当我用浏览器打开相同的网址时，我得到: 沃森错误!! 遇到错误!! 无法与 Watson 通信。 怎么了？会不会和配置有关？或者服务器宕机了？

Answer 1

Any hints or debugging suggestions would be of great help.

1. 使用网络浏览器...或 curl 实用程序尝试相同的请求。

2. 捕获并输出错误流的内容。

<小时/>

我不认为这是造成您问题的原因，但无论如何这是错误的:

DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(query);
wr.flush();

您正在写入需要文本 (JSON) 的 API。因此，您应该使用 Writer，而不是数据(二进制)输出流:

Writer wr = new OutputStreamWriter(con.getOutputStream(), "LATIN-1");
wr.write(query);
wr.flush();