多线程及线程并发库Executors

1.join() 优先执行这个线程

2.yield() 让出本次执行时间片

3.setDaemon(true) 线程可以变成守护线程

import java.util.concurrent.locks.ReentrantLock;

public class thread {
    public static void main(String[] args){
        MyThread myThread = new MyThread();
        Thread thread = new Thread(myThread);
        Thread thread1 = new Thread(myThread);
        thread.start();
        thread1.start();
    }
}
class MyThread implements Runnable{

    private int ticket = 10;
    @Override
    public void run() {
        for (int i=0;i<100;i++){
           method();
            }
        }
    ReentrantLock lock = new ReentrantLock();
        private void method() {
            //锁
            lock.lock();
            try {
                if(ticket>0){
                    ticket--;
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(ticket);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                //解锁
                lock.unlock();
            }
    }

}

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线程池

线程池的作用：

1.降低资源消耗

重复利用已创建的线程降低线程创建和销毁造成的消耗

2.提高响应速度

当任务到达时，不需要创建线程就可以立刻执行

3.提高线程的可管理性

对线程池可以进行统一分配，调优

Executors类

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/*
*  线程池
* */
public class Demo {

    public static void main(String[] args) {
//        创建单线程
//        ExecutorService es = Executors.newSingleThreadExecutor();
//        创建固定线程
//        ExecutorService es = Executors.newFixedThreadPool(2);
//        创建缓存线程无大小
//        ExecutorService es = Executors.newCachedThreadPool();
        ScheduledExecutorService es = Executors.newScheduledThreadPool(3);
//        es.execute(new demo1());
//        es.execute(new demo1());
//        调度,延迟3秒执行
        es.schedule(new demo1(),3000, TimeUnit.MILLISECONDS);
        es.shutdown();
    }
}
class demo1 implements Runnable{

    @Override
    public void run() {
        for (int i=0;i<10;i++){
            System.out.println(Thread.currentThread().getName()+"---"+i);
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}