java - HttpsURLConnection 连接问题

Question

我遇到了似乎无法解决的 HttpsURLConnection 问题。基本上，我正在向服务器发送一些信息，如果其中一些数据有误，服务器会向我发送一个 500 响应代码。但是，它还在响应中发送了一条消息，告诉我哪一位数据是错误的。问题是当我读入消息时消息总是空的。我认为这是因为在读取流之前总是抛出 filenotfound 异常。我对吗？我也尝试阅读错误流，但这始终是空的。这是一个 fragment :

    conn = (HttpsURLConnection) connectURL.openConnection();
    conn.setDoOutput(true);
    conn.setConnectTimeout(30000);
    conn.setReadTimeout(30000);
    conn.setRequestMethod("POST");
    conn.setRequestProperty("Content-Length",
         Integer.toString(outString.getBytes().length));
    DataOutputStream wr = new DataOutputStream(conn
      .getOutputStream());
    wr.write(outString.getBytes());
    wr.flush();
    wr.close();
    if(conn.getResponseCode>400{

    String response = getErrorResponse(conn);

    public String getErrorResponse(HttpsURLConnection conn) {
    Log.i(TAG, "in getResponse");
    InputStream is = null;
    try {

     //is = conn.getInputStream();
    is = conn.getErrorStream();
    // scoop up the reply from the server
    int ch;
    StringBuffer sb = new StringBuffer();
    while ((ch = is.read()) != -1) {
     sb.append((char) ch);
    }
    //System.out.println(sb.toString());
    return sb.toString();
    // return conferenceId;
   }
    catch (Exception e){
    e.printStackTrace();
    }
    }

Answer 1

所以只是为了跟进这个，这是我解决它的方法:

public static String getResponse(HttpsURLConnection conn) {
    Log.i(TAG, "in getResponse");
    InputStream is = null;
    try {
        if(conn.getResponseCode()>=400){
            is = conn.getErrorStream();
        }
        else{
            is=conn.getInputStream();
        }
        ...read stream...
}

似乎像这样调用它们会产生一个带有消息的错误流。感谢您的建议!