多线程概念与编程

Posted 2020-10-21 chensr

一、多线程的三种实现方法

1、继承Thread类

public class MyThread extends Thread {
    @Override
    public void run() {
        try {
            Thread.sleep(1000);
            System.out.println("我是Thread");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        MyThread myThread = new MyThread();
        myThread.start();
        System.out.println("结束main");
    }

}

2、实现Runnable接口

public class MyRunnable implements Runnable {

    @Override
    public void run() {
        try {
            Thread.sleep(1000);
            System.out.println("我是runnable");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        MyRunnable myRunnable = new MyRunnable();
        new Thread(myRunnable).start();
        System.out.println("结束main");
    }

}

3、实现Callable接口

public class MyCallable implements Callable<Object> {

    @Override
    public Object call() throws Exception {
        Thread.sleep(1000);
        System.out.println("我是Callabel");
        return "我是Callabel";
    }
    
    public static void main(String[] args) throws Exception {
        ExecutorService  pool = Executors.newCachedThreadPool();
        MyCallable myCallable = new MyCallable();
        pool.submit(myCallable);    
//        Future<Object> f = pool.submit(myCallable);
//        System.out.println(f.get().toString());    
        System.out.println("main结束");
    }
}

注：当用Future去接收call()返回值，该方法是阻塞的，即先打印“我是Callable”再打印“main结束”