java - 将文件从客户端复制到服务器

Question

我正在尝试用 Java 将文件从客户端复制到服务器，如下所示:

客户:

public class Client {

    public static void main(String[] args) throws Exception {
        String fileName = "D:\\6282.mp3";

        try {

        } catch (Exception e) {
            Scanner scanner = new Scanner(System.in);
            String file_name = fileName;

            File file = new File(file_name);
            Socket socket = new Socket("localhost", 3332);
            ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
            ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());

            oos.writeObject(file.getName());

            FileInputStream fis = new FileInputStream(file);
            byte[] buffer = new byte[Server.BUFFER_SIZE];
            Integer bytesRead = 0;

            while ((bytesRead = fis.read(buffer)) > 0) {
                oos.writeObject(bytesRead);
                oos.writeObject(Arrays.copyOf(buffer, buffer.length));
            }

            oos.close();
            ois.close();
            System.exit(0);
        }

    }

}

服务器:

public class Server extends Thread {

    public static final int PORT = 3332;
    public static final int BUFFER_SIZE = 626;

    @Override
    public void run() {
        try {
            ServerSocket serverSocket = new ServerSocket(PORT);

            while (true) {
                Socket s = serverSocket.accept();
                saveFile(s);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void saveFile(Socket socket) throws Exception {
        ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
        ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
        FileOutputStream fos = null;
        byte[] buffer = new byte[BUFFER_SIZE];

        // 1. Read file name.  
        Object o = ois.readObject();

        if (o instanceof String) {
            fos = new FileOutputStream(o.toString());
        } else {
            throwException("Something is wrong");
        }

        // 2. Read file to the end.  
        Integer bytesRead = 0;

        do {
            o = ois.readObject();

            if (!(o instanceof Integer)) {
                throwException("Something is wrong");
            }

            bytesRead = (Integer) o;

            o = ois.readObject();

            if (!(o instanceof byte[])) {
                throwException("Something is wrong");
            }

            buffer = (byte[]) o;

            // 3. Write data to output file.  
            fos.write(buffer, 0, bytesRead);

        } while (bytesRead == BUFFER_SIZE);

        System.out.println("File transfer success");

        fos.close();

        ois.close();
        oos.close();
    }

    public static void throwException(String message) throws Exception {
        throw new Exception(message);
    }

    public static void main(String[] args) {
        new Server().start();
    }
}

当我运行时，我得到:

run:
BUILD SUCCESSFUL (total time: 0 seconds)

但是什么也没发生。这是我第一次使用客户端-服务器，我不确定我做错了什么。

请帮忙。谢谢。

Answer 1

您的代码中的一些问题是:

对于客户端来说，你已经将整个代码写在catch block 中，除非发生异常，否则该代码不会起作用。

您正尝试在此处传递文件名而不是文件本身。

oos.writeObject(file.getName());

您需要运行服务器，然后运行客户端。这是一个示例工作代码:

客户:

public class Client {

    public static void main(String[] args) throws Exception {
        String fileName = "C:\\2048.jpg";

        try {
            File file = new File(fileName);
            Socket socket = new Socket("localhost", 3332);
            byte[] mybytearray = new byte[(int) file.length()];
            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
            bis.read(mybytearray, 0, mybytearray.length);
            OutputStream os = socket.getOutputStream();
            os.write(mybytearray, 0, mybytearray.length);
            os.flush();
            os.close();
        } catch (Exception e) {
        }

    }
}

服务器:

public class Server extends Thread {

    public static final int PORT = 3332;
    public static final int BUFFER_SIZE = 626;

    @Override
    public void run() {
        try {
            ServerSocket serverSocket = new ServerSocket(PORT);
            while (true) {
                Socket s = serverSocket.accept();
                saveFile(s);
            }
        } catch (Exception e) {
        }
    }

    private void saveFile(Socket socket) throws Exception {
        InputStream ois = socket.getInputStream();
        FileOutputStream fos = new FileOutputStream("C:\\2049.jpg");;

        byte[] mybytearray = new byte[1024];
        System.out.println("Reading file from server...");
        BufferedOutputStream bos = new BufferedOutputStream(fos);
        int bytesRead;
        while ((bytesRead = ois.read(mybytearray)) != -1) {
            bos.write(mybytearray);
        }

        bos.close();
        System.out.println("Writing file complete...");

    }

    public static void main(String[] args) {
        new Server().start();
    }
}