创建线程的三种方式

1、直接继承Thread

package newthrow;
class MyThread extends Thread {
    MyThread(String name) {
        super(name);
    }
    public void run() {
        int i = 0;
        while(i < 20) {
            System.out.println(Thread.currentThread() + " i = " + i);
            i++;
        }
    }
}
public class Demo1 {

    public static void main(String[] args) throws Exception {
        MyThread t1 = new MyThread("t1");
        t1.start();
        Thread.sleep(1);
        System.out.println(Thread.currentThread());
    }

}

线程的调度机制是非确定性的。

几次运行的结果不一样，结果不可预料，可以自己试一下。

2、实现Runnable接口

class MyThread implements Runnable {
    public void run() {
        int i = 0;
        while(i < 20) {
            System.out.println(Thread.currentThread() + " i = " + i);
            i++;
        }
    }
}
public class Demo1 {

    public static void main(String[] args) throws Exception {
        Thread t1 = new Thread(new MyThread(),"t1");
        t1.start();
        Thread.sleep(1);
        System.out.println(Thread.currentThread());
    }

}

Runnable接口定义任务，线程驱动任务。

3、实现Callable接口

class Mycallable implements Callable<Integer> {
    public Integer call() {
        return 1+1;
    }
}
public class Demo6 {
    public static void main(String[] args) throws Exception {
        ExecutorService es = Executors.newSingleThreadExecutor();
        Future<Integer> f = es.submit(new Mycallable());
        System.out.println(f.get());
        es.shutdown();
    }
}