Java多线程详解举例说明

车站三个窗口买票

方法一：通过Thread接口进行多线程

class Window4 extends Thread {


    private static int ticket = 100;

    @Override
    public void run() {

        while (true) {

            show();
        }

    }
    private static synchronized void show(){//同步监视器：Window4.class
        //private synchronized void show(){ //同步监视器：t1,t2,t3。此种解决方式是错误的
        if (ticket > 0) {

            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            System.out.println(Thread.currentThread().getName() + "：卖票，票号为：" + ticket);
            ticket--;
        }
    }
}
public class WindowsTest {
    public static void main(String[] args) {
        Window4 t1 = new Window4();
        Window4 t2 = new Window4();
        Window4 t3 = new Window4();


        t1.setName("窗口1");
        t2.setName("窗口2");
        t3.setName("窗口3");

        t3.start();
        t2.start();
        t1.start();

    }
}

结果：

方法二继承Runable接口：

class Window3 implements Runnable {

    private static int ticket = 100;

    @Override
    public void run() {
        while (ticket>0) {

            show();

        }
    }

    private  synchronized void show(){//同步监视器：this
        //synchronized (this){

        if (ticket > 0) {

            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            ticket--;
            System.out.println(Thread.currentThread().getName() + ":卖票，票号为：" + ticket);


        }
        //}
    }
}

public class WindowsTest3 {
    public static void main(String[] args) {
        Window3 w = new Window3();

        Thread t1 = new Thread(w);
        Thread t2 = new Thread(w);
        Thread t3 = new Thread(w);

        t1.setName("窗口1");
        t2.setName("窗口2");
        t3.setName("窗口3");

        t1.start();
        t2.start();
        t3.start();
    }

}

结果：

总结

无论哪种方法实现都需要进行synchronized进行修饰，这是为了保护线程安全，不然会同时涌入多个线程，还有用Thread接口继承的时候，我们需要将show方法声明为static静态方法，不然new三个对象，会创建三个方法，还是会发生多线程涌入。