java 多线程

1 两种实现方式：

image.png

2 创建多个线程如何正确执行？
2.1错误示例：多个线程都执行一遍同一个任务

package io.github.lxqjss;

public class ThreadTest extends Thread{

    private int coutNum = 5;
    @Override
    public void run() {
        while (coutNum>0){
            coutNum--;
            System.out.println("还剩下票数:"+coutNum);
        }

    }

    public static  void main(String []args){
        ThreadTest threadTest1 = new ThreadTest();
        ThreadTest threadTest2 = new ThreadTest();
        ThreadTest threadTest3 = new ThreadTest();

        threadTest1.start();
        threadTest2.start();
        threadTest3.start();

        System.out.println("ok");
    }

}

执行截图：

image.png

2.2 让多个线程交替执行某个任务，达到最大化利用cpu才是目的

package io.github.lxqjss;

public class RunnableTest implements Runnable{
    private int coutNum = 5;
    @Override
    public void run() {
        while (coutNum>0){
            coutNum--;
            System.out.println(Thread.currentThread().getName()+"还剩下票数:"+coutNum);
        }

    }

    public static  void main(String []args){
        RunnableTest runnableTest = new RunnableTest();

        Thread threadTest1 = new Thread(runnableTest,"1号");
        Thread threadTest2 = new Thread(runnableTest,"2号");
        Thread threadTest3 = new Thread(runnableTest,"3号");
        threadTest1.start();
        threadTest2.start();
        threadTest3.start();

//        System.out.println("ok");
    }
}

image.png