Question

我的节目停在了以下一行：

InputStream is = conn.getInputStream();

控制台上没有弹出错误消息或显示任何输出。我在Red Hat Enterprise Linux Server 7.4版上运行Eclipse Oxygen 4.7.0。

 public static void solveInstance(String instanceName){
            // solve a problem instance
            try{
                String query_url = "http://localhost:8807/scheduler";

                // read Request to a JSON Object
                JSONParser parser = new JSONParser();
                JSONObject request = (JSONObject) parser.parse(new FileReader(instanceName));

                // open connection
                URL url = new URL(query_url);
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setConnectTimeout(5000);
                conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
                conn.setDoOutput(true);
                conn.setRequestMethod("POST");

                // POST Request
                OutputStream os = conn.getOutputStream();
                OutputStreamWriter osw =  new OutputStreamWriter(os, "UTF-8");
                osw.write(request.toString());
                osw.close();

                // Get Response
                InputStream is = conn.getInputStream();
                InputStreamReader isr = new InputStreamReader(is);
                BufferedReader in = new BufferedReader(isr);

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

                // Write response to a file
                JSONObject jsonObj = (JSONObject) parser.parse(response.toString());
                String responseFile = /path_to_result/result.json;

                FileWriter fileWriter = new FileWriter(responseFile);
                fileWriter.write(jsonObj.toString());
                fileWriter.flush();
                fileWriter.close();

                System.out.println("Solved" + instanceName);
            }
            catch(Exception e) {
                System.out.println(e);
            }
        }

我注意到问了类似的问题InputStream is = httpURLConnection.getInputStream(); stop working 但这是针对Android而没有给出解决方案。

有没有人对此有所了解？不要犹豫，在我的代码中指出其他任何错误。

非常感谢！

Answer 1

您的服务器没有响应。

使用conn.setReadTimeout(5000)（比如说）设置读取超时是明智的。根据需要调整超时。

Answer 2

检查响应代码

int response = connection.getResponseCode();

如果您收到301，则表示您的资源已重定向。尝试将URI从http更改为https。

对我来说有帮助。

为什么HttpURLConnection.getInputStream停止在Java中工作

2 个答案: