使用Java中的套接字将文件从服务器下载到客户端

我有一些代码可以将文件从客户端上传到服务器，并且工作正常，上传的文件保存在服务器文件夹Server中，现在想将服务器文件夹中存在的文件下载到客户端文件夹，但是不知道该怎么做。请帮忙

此服务器代码说明了从客户端到服务器的下载文件：

  public static void downloadFile() throws Exception{
    try {
        fileEvent = (FileEvent) inputStream.readObject();
        if (fileEvent.getStatus().equalsIgnoreCase("Error")) {
            System.out.println("Error occurred ..So exiting");
            System.exit(0);
        }
        String outputFile = fileEvent.getDestinationDirectory() + fileEvent.getFilename();
        if (!new File(fileEvent.getDestinationDirectory()).exists()) {
            new File(fileEvent.getDestinationDirectory()).mkdirs();
        }

        int filenamelength = dis.readInt();
        String filename = makeString(filenamelength, dis);

        dstFile = new File(path + filename);
        fileOutputStream = new FileOutputStream(dstFile);
        fileOutputStream.write(fileEvent.getFileData());
        fileOutputStream.flush();
        fileOutputStream.close();
        System.out.println("Output file : " + outputFile + " is successfully saved ");
        Thread.sleep(3000);
        System.exit(0);

    } catch (IOException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

这是用于将文件从客户端上传到服务器的客户端代码：

 public static void sendFile() throws Exception {
    dos.writeInt(6);
    dos.writeChars("upload");

    fileEvent = new FileEvent();
   String fileName = sourceFilePath.substring(sourceFilePath.lastIndexOf("/") + 1, sourceFilePath.length());
    String path = sourceFilePath.substring(0, sourceFilePath.lastIndexOf("/") + 1);
    fileEvent.setDestinationDirectory(destinationPath);
    fileEvent.setFilename(fileName);
    fileEvent.setSourceDirectory(sourceFilePath);
    File file = new File(sourceFilePath);
    if (file.isFile()) {
        try {
            DataInputStream diStream = new DataInputStream(new FileInputStream(file));
            long len = (int) file.length();
            byte[] fileBytes = new byte[(int) len];
            int read = 0;
            int numRead = 0;
            while (read < fileBytes.length && (numRead = diStream.read(fileBytes, read,
                    fileBytes.length - read)) >= 0) {
                read = read + numRead;
            }
            fileEvent.setFileSize(len);
            fileEvent.setFileData(fileBytes);
            fileEvent.setStatus("Success");
        } catch (Exception e) {
            e.printStackTrace();
            fileEvent.setStatus("Error");
        }
    } else {
        System.out.println("path specified is not pointing to a file");
        fileEvent.setStatus("Error");
    }
    //Now writing the FileEvent object to socket
    try {

        outputStream.writeObject(fileEvent);

        System.out.println("Choose file: ");
        String str = scanner.nextLine();

        String[] parts = str.split(Pattern.quote("\\"));
        String filename = parts[parts.length - 1];

        dos.writeInt(filename.length());
        dos.writeChars(filename);

        Thread.sleep(3000);
        System.exit(0);
    } catch (IOException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

}