Question

For some of HTTP requests from clients, there’re very complex business logic in server side.
Some of these business logics doesn’t require to response to the client immediately, like sending a email to somebody. Can I put those tasks in an asynchronous method,so I only need to ensure that they had been executed,I don’t need to wait all tasks complete to respond to the user.

Updated: Some people asked about the framework I am using. I am using Struts2 + Spring.

Answer 1

I don’t know what framework you’re using, but, in basic Java, you can just create a new Thread:

interface MyTaskCallback {
    void myTaskCallback();
}
class MyTask implements Runnable {  
    MyTaskCallback callback;
    Thread me;
    public MyTask(MyTaskCallback callback) {
        this.callback = callback;
        this.me = new Thread();
    }

    public void start() {
        this.me = new Thread(this);
        this.me.start();
    }

    public void stop() {
        try {
            this.me.join(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public void run() {
        // Calls here will not block the other threads
        sendEmailRequest();
        callback.myTaskCallback();
    }
}

class Main implements MyTaskCallback {
    public void foo() {
        MyTask m = new MyTask(this);
        m.start();
    }

    public void myTaskCallback() {
        // called when MyTask completes
    }
}