java SocketException：来自服务器的意外文件结尾

Question

我遇到了Java HttpURLConnection的问题。我正在从客户端向服务器发送音频文件（midi格式）。这部分工作得很好。之后我想在服务器端使用该文件来编写我所编写的算法。该算法分析midi文件的类型和播放乐器。在分析midi文件时，我得到了一个自编写类StringArrayUndString的对象。在这个类中，只存在一个String []（用于播放乐器）和一个String（用于类型）。如果我只是将midi文件发送到服务器并发送响应200代码，该程序完全正常。但是，如果我想在从客户端接收midi文件后再分析它，然后以StringArrayUndString-object的形式发回分析的数据，我会收到以下错误：java.net.SocketException: Unexpected end of file from server甚至响应代码都没有所示。该文件仍然正确传输。现在说话够了，这里是代码：

private static void sendPOST() throws IOException, ClassNotFoundException{
        final int mid = 1;
        final String POST_URL = "http://localhost:8080/musiker/hörprobe?mid="+mid;
        final File uploadFile = new File("C://Users//Felix Ulbrich//Desktop//EIS Prototype MIDIs//Pop//IWantItThatWay.mid");
        String boundary = Long.toHexString(System.currentTimeMillis()); 
        String CRLF = "\r\n";
        String charset = "UTF-8";
        URLConnection connection = new URL(POST_URL).openConnection();
        connection.setDoOutput(true);
        connection.setDoInput(true);
        connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
        connection.setConnectTimeout(0);
        connection.setReadTimeout(0);
        try (
            OutputStream output = connection.getOutputStream();
            PrintWriter writer = new PrintWriter(new OutputStreamWriter(output, charset), true);
        ) {
            writer.append("--" + boundary).append(CRLF);
            writer.append("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"" + uploadFile.getName() + "\"").append(CRLF);
            writer.append("Content-Length: " + uploadFile.length()).append(CRLF);
            writer.append("Content-Type: " + URLConnection.guessContentTypeFromName(uploadFile.getName())).append(CRLF);
            writer.append("Content-Transfer-Encoding: binary").append(CRLF);
            writer.append(CRLF).flush();
            Files.copy(uploadFile.toPath(), output);
            output.flush();
            int responseCode = ((HttpURLConnection) connection).getResponseCode();
            if(responseCode == ((HttpURLConnection)connection).HTTP_OK){
                InputStream input = connection.getInputStream();
                ObjectInputStream ois = new ObjectInputStream(input);
                Object object = ois.readObject();
                if(object instanceof StringArrayUndString){
                    StringArrayUndString Daten = (StringArrayUndString)object;
                    for(int i = 0; i<Daten.array.length; i++){
                        System.out.println("Instrument: "+Daten.array[i]);
                    }
                    System.out.println("Genre: "+Daten.string);
                }
            }
            System.out.println("Response code: ["+ responseCode + "]");
        }
    }

这是客户端。

System.out.println("Ich bin am Anfang!");
                    int hörprobenzaehler = 0;
                    Statement hoerprobenzaehlen = myConn.createStatement();
                    String hoerprobensql = "select MAX(hpid) from hörprobendaten where musiker_mid='"+musikerid+"'";
                    ResultSet anzahl = hoerprobenzaehlen.executeQuery(hoerprobensql);
                    while(anzahl.next()){
                        hörprobenzaehler = anzahl.getInt("max(hpid)");
                    }
                    String CRLF = "\r\n";
                    int fileSize = 0;
                    System.out.println("Ich erzeuge das File!");
                    String FILE_TO_RECEIVED = "C://root//m"+musikerid+"hp"+(hörprobenzaehler+1)+".mid";
                    File f = new File(FILE_TO_RECEIVED);
                    if (!f.exists()) {
                        f.createNewFile();
                    }
                    System.out.println("File erzeugt!");
                    InputStream input = t.getRequestBody();
                    String nextLine = "";
                    do {
                        nextLine = readLine(input, CRLF);
                        if (nextLine.startsWith("Content-Length:")) {
                            fileSize = 
                                Integer.parseInt(
                                    nextLine.replaceAll(" ", "").substring(
                                        "Content-Length:".length()
                                    )
                                );
                        }
                        System.out.println(nextLine);
                    } while (!nextLine.equals(""));
                    byte[] midFileByteArray = new byte[fileSize];
                    int readOffset = 0;
                    while(readOffset < fileSize){
                        int bytesRead = input.read(midFileByteArray, readOffset, fileSize);
                        readOffset += bytesRead;
                    }
                    System.out.println("Array gelesen!");
                    BufferedOutputStream bos = 
                        new BufferedOutputStream(new FileOutputStream(FILE_TO_RECEIVED));

                    bos.write(midFileByteArray, 0, fileSize);
                    System.out.println("Datei geschrieben!");
                    InstrumentIdentifier II = new InstrumentIdentifier(FILE_TO_RECEIVED);
                    DynamicIdentifier DI = new DynamicIdentifier(FILE_TO_RECEIVED);
                    MusicalTextureIdentifier MTI = new MusicalTextureIdentifier(FILE_TO_RECEIVED);
                    MidiAnalyzer analyzer = new MidiAnalyzer(II, DI, MTI);
                    StringArrayUndString Daten =analyzer.analyze();
                    System.out.println("File analysiert!");
                    bos.flush();
                    bos.close();
                    OutputStream output = t.getResponseBody();
                    System.out.println("Response Header ist raus!");
                    ObjectOutputStream oos = new ObjectOutputStream(output);
                    t.sendResponseHeaders(200, 0);
                    oos.writeObject(Daten);
                    System.out.println("Response Object ist raus!");
                    oos.flush();
                    oos.close();
                    System.out.println("Fertig!");

这是服务器端。

在服务器端，我使用了一些System.out.println命令，所以我会看到我的程序停止工作的位置，看起来，它会在System.out.println("Datei geschrieben!");之后停止。如果有人知道解决方案，请告诉我:)。非常感谢你。

问候，Gizpo