获取java.io.IOException：服务器返回的HTTP响应代码：400

Question

我正在尝试将对multipart / form-data的POST请求转换为Java程序，并且收到java.io.IOException：服务器返回了HTTP响应代码：400

// Connect to the web server endpoint
            URL serverUrl =
                    new URL("http://testurl/start-date/2017-01-01/upload");
            HttpURLConnection urlConnection = (HttpURLConnection) serverUrl.openConnection();

            //String boundaryString = "----SomeRandomText";
            String fileUrl = "C:/Users/V70070/Documents/ALL FILES/Rates/MAC2291_RATES.csv";
            String encodedCredentials = "Basic dGVzdDpwYXNzd29yZA==";
            File logFileToUpload = new File(fileUrl);

// Indicate that we want to write to the HTTP request body
            urlConnection.setDoOutput(true);
            urlConnection.setRequestProperty ("Authorization", encodedCredentials);

            urlConnection.setRequestMethod("POST");
            urlConnection.addRequestProperty("Content-Type", "multipart/form-data");

            OutputStream outputStreamToRequestBody = urlConnection.getOutputStream();
            BufferedWriter httpRequestBodyWriter =
                    new BufferedWriter(new OutputStreamWriter(outputStreamToRequestBody));

// Include value from the myFileDescription text area in the post data
            httpRequestBodyWriter.write("Content-Disposition: form-data; name=\"fileData\"; Content-Type: text/plain; filename=\"MAC2291_RATES.csv\"");

// Include the section to describe the file
//            httpRequestBodyWriter.write("Content-Disposition: form-data;"
//                    + "name=\"myFile\";"
//                    + "filename=\"" + logFileToUpload.getName() + "\""
//                    + "\nContent-Type: text/plain\n\n");
//            httpRequestBodyWriter.flush();

// Write the actual file contents
            FileInputStream inputStreamToLogFile = new FileInputStream(logFileToUpload);

            int bytesRead;
            byte[] dataBuffer = new byte[1024];
            while ((bytesRead = inputStreamToLogFile.read(dataBuffer)) != -1) {
                outputStreamToRequestBody.write(dataBuffer, 0, bytesRead);
            }

            outputStreamToRequestBody.flush();

// Mark the end of the multipart http request
            //httpRequestBodyWriter.write("\n--" + boundaryString + "--\n");
            httpRequestBodyWriter.flush();


            // Read response from web server, which will trigger the multipart HTTP request to be sent.
            BufferedReader httpResponseReader =
                    new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
            String lineRead;
            while((lineRead = httpResponseReader.readLine()) != null) {
                System.out.println(lineRead);
            }

            // Close the streams
            outputStreamToRequestBody.close();
            httpRequestBodyWriter.close();
}

从Web服务器读取响应时出现异常

BufferedReader httpResponseReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));

任何帮助，我们将不胜感激。 TIA