java_线程的同步机制

1.同步代码块：

　　使用synchronized包住可能会出现安全问题的代码

import static java.lang.Thread.sleep;

class Test01{
    public static void main(String[] args) {
        ThreadTest threadTest = new ThreadTest();
        Thread thread1 = new Thread(threadTest);
        Thread thread2 = new Thread(threadTest);
        Thread thread3 = new Thread(threadTest);
        thread1.setName("窗口一");
        thread2.setName("窗口二");
        thread3.setName("窗口三");
        thread1.start();
        thread2.start();
        thread3.start();
    }

}
class ThreadTest implements Runnable{

    /**
     * 实现三个窗口买票
     */
    private int ticket = 100;

    @Override
    public void run() {
            while (true){
                synchronized (this) {
                if(ticket>0) {
                    try {
                        sleep(100);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + ticket);

                    ticket--;
                }else{
                    break;
                }
            }
        }
    }
}

 2.同步方法

在方法上使用synchronized修饰

import static java.lang.Thread.sleep;

public class Test02 {
    public static void main(String[] args) {
        ThreadTest1 threadTest1 = new ThreadTest1();
        Thread thread = new Thread(threadTest1);
        Thread thread1 = new Thread(threadTest1);
        Thread thread2 = new Thread(threadTest1);
        thread.setName("窗口一");
        thread1.setName("窗口二");
        thread2.setName("窗口三");
        thread1.start();
        thread.start();
        thread2.start();
    }
}
class ThreadTest1 implements Runnable{
    private int ticket = 100;
    @Override
    public void run() {
        while (true){
           newrun();
        }
    }

    private synchronized void newrun() {
        if(ticket>0) {
            try {
                sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + ticket);
            ticket--;
        }
    }

}