写一段java多线程

Java中的多线程可以通过继承Thread类或实现Runnable接口来实现。下面是一个简单的例子，通过实现Runnable接口来创建一个多线程程序：

public class MyThread implements Runnable {
    private String name;

    public MyThread(String name) {
        this.name = name;
    }

    public void run() {
        System.out.println("Thread " + name + " is running");
        for (int i = 0; i < 5; i++) {
            System.out.println("Thread " + name + " prints " + i);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("Thread " + name + " is finished");
    }
}

在main函数中启动多个线程：

public static void main(String[] args) {
    Thread t1 = new Thread(new MyThread("A"));
    Thread t2 = new Thread(new MyThread("B"));
    t1.start();
    t2.start();
}

运行结果如下：

Thread A is running
Thread B is running
Thread A prints 0
Thread B prints 0
Thread A prints 1
Thread B prints 1
Thread A prints 2
Thread B prints 2
Thread A prints 3
Thread B prints 3
Thread A prints 4
Thread B prints 4
Thread A is finished
Thread B is finished