Java socket服务器客户端到客户端文件传输

我不确定我想做的事情是否可行 . 我想要一个套接字服务器运行，多个客户端可以连接到它 . 客户端A将文件拖放到他的GUI上，客户端B会弹出一个询问他是否要接收该文件的弹出窗口 . 如果约定的客户端A开始上传文件，则客户端B开始直接下载文件 . 这可能吗？该文件应该首先转移到服务器？如果我将文件发送到服务器它可以工作，但当我尝试将文件发送到客户端B时，我得到以下内容：

java.net.ConnectException: Connection timed out: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:579)
    at java.net.Socket.connect(Socket.java:528)
    at java.net.Socket.<init>(Socket.java:425)
    at java.net.Socket.<init>(Socket.java:241)

这是上传类：

public Upload(String addr, int port, File filepath, OpenChatFrame frame) {
        super();
        try {
            file = filepath;
            ui = frame;
            socket = new Socket(InetAddress.getByName(addr), port);
            Out = socket.getOutputStream();
            In = new FileInputStream(filepath);
            length = file.length();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    @Override
    public void run() {
        try {
            byte[] buffer = new byte[1024];

            int count;

            ui.jProgressBar1.setMaximum((int) length);

            while ((count = In.read(buffer)) >= 0) {
                Out.write(buffer, 0, count);
                bytes += count;
                ui.jProgressBar1.setValue(bytes);

            }
            Out.flush();


            if (In != null) {
                In.close();
            }
            if (Out != null) {
                Out.close();
            }
            if (socket != null) {
                socket.close();
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

这是下载类：

public Download(String saveTo, OpenChatFrame ui) {
    try {
        server = new ServerSocket(0);
        port = server.getLocalPort();
        this.saveTo = saveTo;
        this.ui = ui;
    } catch (IOException ex) {
        //TODO: catch
    }
}

@Override
public void run() {
    try {
        socket = server.accept();
        System.out.println("Download : " + socket.getRemoteSocketAddress());

        In = socket.getInputStream();
        Out = new FileOutputStream(saveTo);

        byte[] buffer = new byte[1024];
        int count;

        while ((count = In.read(buffer)) >= 0) {
            Out.write(buffer, 0, count);
        }

        Out.flush();

        File physicalFile = new File(saveTo);
        System.out.println("FILE FILENAME: " + physicalFile.getName());
        System.out.println("saveTo: " + saveTo);


        if (Out != null) {
            Out.close();
        }
        if (In != null) {
            In.close();
        }
        if (socket != null) {
            socket.close();
        }
    } catch (Exception ex) {
        //TODO: catch
    }
}