您应该
httpCon.connect();仅在将参数写入主体后才调用，而不是之前。您的代码应如下所示：
URL url = new URL("http://localhost:4567/");HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();httpCon.setDoOutput(true);httpCon.setRequestMethod("POST");OutputStream os = httpCon.getOutputStream();OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8"); osw.write("Just Some Text");osw.flush();osw.close();os.close(); //don't forget to close the OutputStreamhttpCon.connect();//read the inputstream and print itString result;BufferedInputStream bis = new BufferedInputStream(httpCon.getInputStream());ByteArrayOutputStream buf = new ByteArrayOutputStream();int result2 = bis.read();while(result2 != -1) { buf.write((byte) result2); result2 = bis.read();}result = buf.toString();System.out.println(result);
