多线程（二）

线程优先级：

       线程虽然有优先级，但是并不能保证一定先执行，只是为优先执行提供可能。

       优先级范围 ：1—10   数字越大，优先级越高。

public class Demo extends Thread{

		@Override
		public void run() {
			// TODO Auto-generated method stub
			System.out.println(Thread.currentThread().getName()+"在执行！");
		}
	public static void main(String[] args) {
		Demo d1 = new Demo();
		d1.setName("线程一");
//		d1.setPriority(10);
//		d1.setPriority(MAX_PRIORITY);
		d1.start();
		
		Demo d2 = new Demo();
		d2.setName("线程二");
//		d2.setPriority(MIN_PRIORITY);
		d2.start();
		
		Demo d3 = new Demo();
		d3.setName("线程三");
		d3.start();
		
		System.out.println(Thread.currentThread().getName()+"在执行！=========");
	}
}

public class MyRunnable1 implements Runnable {

	@Override
	public void run() {
		// TODO Auto-generated method stub
		for (int i = 0; i < 500; i++) {
			System.out.println((i+1)+":1===线程");
		}
	}

}

package d87_thread_1;

public class MyRunnable2 implements Runnable {

	@Override
	public void run() {
		// TODO Auto-generated method stub
		for (int i = 0; i < 500; i++) {
			System.out.println((i+1)+":第二个线程在执行");
		}
	}

}

package d87_thread_1;

public class MyRunTest {
	public static void main(String[] args) {
		MyRunnable1 my1 = new MyRunnable1();
		MyRunnable2 my2 = new MyRunnable2();
		
		Thread t1 = new Thread(my1);
		Thread t2 = new Thread(my2);
		
//		t1.setPriority(Thread.MAX_PRIORITY);;
		
		t1.start();
		t2.start();
	}
}

线程休眠----------------------------------------------------------------

package Test_Thread;

public class Thread1 implements Runnable{

    @Override
    public void run() {
        for (int i = 0;i<20;i++){
            System.out.println(Thread.currentThread().getName()+i);
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        Thread1 t = new Thread1();
        Thread f = new Thread(t);
        f.start();
    }
}

线程休眠

package Test_Thread;

public class Thread2 implements Runnable {
    @Override
    public void run() {
        for (int i = 0;i<50;i++){
            System.out.println(Thread.currentThread().getName()+"--->"+i);
            if(i%4==0){
                Thread.yield();
            }
        }
    }


    public static void main(String[] args) {
        Thread2 t2 = new Thread2();
        Thread x = new Thread(t2);
        Thread p = new Thread(t2);

        x.setName("线程A");
        p.setName("线程B");

        x.start();
        p.start();
    }
}

线程的同步：

但过多的同步会产生死锁。

 

Synchronized 关键字可修饰 同步代码块和同步方法

package Test_Thread.savemoney;

public class Money {
    public static int money = 50;
}

package Test_Thread.savemoney;

public class Getmoney extends Money implements Runnable  {

    public  synchronized void getmoney(){
        if(money>0) {
            money -= 10;
            System.out.println("取出10元，剩余" + money + "元");
        }
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public void run() {
        while (money<300){
            this.getmoney();
        }
    }
}
package Test_Thread.savemoney;

public class Save extends Money implements Runnable {
    public synchronized void savemoney() {
        money += 20;
        System.out.println("存入20元，剩余" + money + "元");
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    public void run() {
        while (money<300){
            this.savemoney();
        }
    }
}
--------------------------------------------------------------------------
package Test_Thread.savemoney;

public class Test {
    public static void main(String[] args) {
        Save s = new Save();
        Thread t1 = new Thread(s);
        Getmoney g = new Getmoney();
        Thread t2 = new Thread(g);

        t1.start();
        t2.start();
    }
}