java - HttpsURLConnection 频繁出现 504 错误

Question

我在 Java-1.8 中使用 HttpsURLconnection 并使用一些参数发布到 URL。很多时候会收到 200 成功响应，但有时会收到 504 网关超时错误。

我为这个错误苦苦挣扎了很长时间。任何指导都会非常有帮助。下面是我正在使用的代码。

public static void sendPostRequest(String url, ResourceRequest resourceRequest,
        ResourceResponse resourceResponse)
{ 
    String token_response = "";

                String grant_password = PrefsPropsUtil.getString("grant.type");
                String client_id = PrefsPropsUtil.getString("client.id");
                String user_name = PrefsPropsUtil.getString("user.name");
                String client_secret = PrefsPropsUtil.getString("client.secret");
                PrintWriter out = resourceResponse.getWriter();
                URL obj = new URL(url);

                System.setProperty("jdk.http.auth.proxying.disabledSchemes", "");
                System.setProperty("jdk.http.auth.tunneling.disabledSchemes", "");
            HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();
               //add request header
                con.setRequestMethod("POST");
              //  con.setRequestProperty("User-Agent", USER_AGENT);
                con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
                String urlParameters = "grant_type=" + grant_password + "&client_id=" + client_id + "&username=&client_secret=" + client_secret;
                // Send post request
                con.setDoOutput(true);
                DataOutputStream wr = new DataOutputStream(con.getOutputStream());
                wr.writeBytes(urlParameters);
                wr.flush();
                wr.close();
                int responseCode = con.getResponseCode();
                BufferedReader in = new BufferedReader(
                        new InputStreamReader(con.getInputStream()));
                String inputLine;
                StringBuffer response = new StringBuffer();
                while ((inputLine = in.readLine()) != null) {
                    response.append(inputLine);
                }
                in.close();
                con.disconnect();
                //print result
                System.out.println(response.toString());
                out.println(response);

}

上面的代码我不知道哪里错了，请指正。

Answer 1

5xx 代码被视为服务器错误。因此，这很可能不是请求方的问题。

504 Gateway Timeout: The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

我建议您检查服务器的代理设置是否正确或上游服务器的稳定性等。从 HttpsURLconnection 中可以说的不多，它看起来很通用。