在Java回调中发送多个文件？

Question

How can I add to the sending queue, for example I choose a file with JFileChooser and then send it in a new thread to the client, and I want to choose another and send it as well. What happens is that it sends the files simultaneously and the output on the client side is broken.

I'd like to be able to add to a "queue" of some sort, so that when the first file is sent, the server will start sending the next one.

Answer 1

A good aproach for socket communication between server->client, is to have 1 thread per client and have this thread reading from a java.util.concurrent.BlockingQueue . Such interface is ideal (just like all the java.util.concurrent objects) for managing multithreading concurrency.

The idea, is that the Server has a ClientThread like this:

class BroadCastThread extends Thread{
    LinkedBlockingQueue<SendFileTask> bcQueue = new LinkedBlockingQueue<>();
    @Override
    public void run() {
        while( true ){
            try {
                SendFileTask task = bcQueue.take();
                task.sendFile();
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    }
    void addTask(SendFileTask rt) throws InterruptedException{
        bcQueue.put(rt);
    }
}
interface SendFileTask{
    void sendFile() throws Exception;
}

And use this by adding tasks to you thread object:

        BroadCastThread bct = new BroadCastThread();
        bct.start();

        //With lambda
        bct.addTask(() -> {
            //Send file code
        });

        //Without lambda
        bct.addTask(new SendFileTask() {
            @Override
            void sendFile() throws Exception {
            //Send file code
            }
        });

You can even store the Socket information with the thread, and pass it throw the task interface, if you want the sendFile method to receive it as parameter.