8.多线程同步方法

1.synchronized加在普通方法上相当于把该方法放在同步代码块synchronized(this)中。

public class sellticket implements Runnable{
    private static int tickets=100;
    private static int x=0;

    public synchronized void sellTicket() {
        while (true){
            if (tickets >0) {
                x++;
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName() + "：正在销售第" + tickets + "张票");
                tickets--;
            }
        }
    }
    @Override
    public void run() {
        //使用这种方式，普通方法不会被锁住
//        sellticket s = new sellticket();
//        s.sellTicket();
        
        sellTicket();
    }
    public static void main(String[] args) {
        //普通方法被锁住
//        sellticket s = new sellticket();
//        Thread t1 = new Thread(s);
//        Thread t2 = new Thread(s);
//        t1.start();
//        t2.start();

        //普通方法没被锁住
        sellticket s = new sellticket();
        sellticket s1 = new sellticket();
        Thread t1 = new Thread(s);
        Thread t2 = new Thread(s1);
        t1.start();
        t2.start();
    }
}

2.synchronized加在静态方法上相当于把该方法放在同步代码块synchronized(类名.class)中。

public class sellticket implements Runnable{
    private static int tickets=100;
    private static int x=0;

    private static synchronized void sellTicket1() {
        while (true) {
            if (tickets >0) {
                x++;
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName() + "：正在销售第" + tickets + "张票");
                tickets--;
            }
        }
    }

    @Override
    public void run() {
        //使用这个方式，普通方法不会被锁住
//        sellticket s = new sellticket();
//        s.sellTicket();

//        sellTicket();
        sellTicket1();
    }

    public static void main(String[] args) {
        //普通方法被锁住
        //静态方法被锁住
        sellticket s = new sellticket();
        Thread t1 = new Thread(s);
        Thread t2 = new Thread(s);
        t1.start();
        t2.start();

        //普通方法没被锁住
        //静态方法被锁住
//        sellticket s = new sellticket();
//        sellticket s1 = new sellticket();
//        Thread t1 = new Thread(s);
//        Thread t2 = new Thread(s1);
//        t1.start();
//        t2.start();
    }
}