Java Runnable 如何实现多线程

在Java中，要实现多线程，可以通过实现Runnable接口或者继承Thread类。下面是两种方法的示例：

1. 实现Runnable接口：

public class MyRunnable implements Runnable {
    private String threadName;

    public MyRunnable(String threadName) {
        this.threadName = threadName;
    }

    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println(threadName + "：" + i);
        }
    }

    public static void main(String[] args) {
        MyRunnable runnable = new MyRunnable("线程1");
        Thread thread1 = new Thread(runnable);
        thread1.start();

        MyRunnable runnable2 = new MyRunnable("线程2");
        Thread thread2 = new Thread(runnable2);
        thread2.start();
    }
}

2. 继承Thread类：

public class MyThread extends Thread {
    private String threadName;

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

    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println(threadName + "：" + i);
        }
    }

    public static void main(String[] args) {
        MyThread myThread = new MyThread("线程1");
        Thread thread1 = new Thread(myThread);
        thread1.start();

        MyThread myThread2 = new MyThread("线程2");
        Thread thread2 = new Thread(myThread2);
        thread2.start();
    }
}

在这两个示例中，我们创建了两个线程，每个线程执行run方法中的代码。main方法中，我们创建了Runnable或Thread对象，并将其传递给Thread类的构造函数。然后调用start()方法启动线程。这将导致线程并行执行run方法中的代码。