java多线程总结

Posted 2020-11-24 shaoyu

一、java多线程创建的两种方式

1.1、使用Thread类的子类

public class ThreadA extends Thread {
    // 在java中可以试用Thread类的子类创建线程，需要重写父类的run方法
    @Override
    public void run() {
        for(int i=0;i<20;i++)
            System.out.print("子线程A"+i+"	");

    }
}

    @Test
    public void hello(){
    //调用直接创建实现，调用start方法即可
        ThreadA threadA = new ThreadA();
        threadA.start();
}

1.2、使用Thread类

    @Test
    public void hello(){
        //使用Thread类必须在创建线程对象时向构造方法中传递一个Runnable接口类的实例
        new Thread(new Runnable() {
            //当线程调用start方法时，就会自动调用run方法
            @Override
            public void run() {
                for(int i=1;i<20;i++)
                    System.out.print("Runnable "+i+"	");
            }
        }).start();
}

二、目标对象与线程的关系

2.1、目标对象和线程完全解耦

    public static void main(String[] args){

        House house = new House();

        house.setNun(10);

        Thread a,b;
        a = new Thread(house);
        b = new Thread(house);

        a.setName("A");
        b.setName("B");

        a.start();
        b.start();
    }



public class House implements Runnable {

    int nun;

    public void setNun(int nun) {
        this.nun = nun;
    }

    @Override
    public void run() {
        String name = Thread.currentThread().getName();
        while (true){
            if("A".equals(name)){
                System.out.println(name+"抢票2张");
                this.nun = this.nun -2;
            }else if("B".equals(name)){
                System.out.println(name+"抢票1张");
                this.nun--;
            }
            System.out.println("还剩 "+ nun +" 张");

            try {
                Thread.sleep(2000L);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            if(nun <= 0)
                return;
        }
    }
}

2.2、目标对象组合线程（弱耦合）

   public static void main(String[] args){

        House house = new House();

        house.student.start();
        house.teacher.start();

    }


public class House implements Runnable {

    Thread student,teacher;

    public House(){
        student = new Thread(this);
        teacher = new Thread(this);
        student.setName("张三");
        teacher.setName("王教授");
    }

    @Override
    public void run() {
        if(Thread.currentThread() == student){
            System.out.println(student.getName() + "正在睡觉，不听讲");
            try {
                Thread.sleep(1000*60*60);
            } catch (InterruptedException e) {
                System.out.println(student.getName() + "被老师叫醒了");
            }
        }else if(Thread.currentThread() == teacher){
            for(int i=0; i<3; i++){
                System.out.println("上课！");
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            student.interrupt();
        }


    }
}