在千锋逆战班学习第二十九天 线程（二）

在千锋"逆战”学习第29天,
每个人生阶段都需要努力去扮好自己的角色,越努力越轻松,越坚强越幸运!
加油!

8(线程同步)有下面代码

class MyThread8 extends Thread{
	private String data;
	public MyThread8(String data) {
		this.data=data;
	}
	public  void run(){

		for(int i=0;i<100;i++) {
			System.out.println(data);
		
		}
	}
}
public class Test8 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Thread t1=new MyThread8("aaa");
		Thread t2=new MyThread8("bbb");
		t1.start();
		t2.start();
	}

}
现希望能够同步的输出aaa和bbb ,即一次输出100个aaa或bbb ,输出这两个字符串时没有交互。
为了达到上述目的,要对原代码进行修改。以下哪些修改方式能够得到想要的结果?
A.把第6行改为public synchronized void run()
B.把run方法中所有的内容都放在synchronized(data)代码块中
C.把run方法中所有的内容都放在synchronized(System.out)代码块中

AC

9 (线程综合)代码改错

class MyThread9 implements Runnable{

	@Override
	public void run() {
		// TODO Auto-generated method stub
		for(int i=0;i<100;i++) {
			this.sleep((int)(Math.random()*1000));
			System.out.println("hello");
		}
	}
}
class MyThread10 implements Runnable{

	@Override
	public void run()throws Exception{
		// TODO Auto-generated method stub
		for(int i=0;i<100;i++) {
			this.sleep((int)(Math.random()*1000));
			System.out.println("world");
		}
	}

}
public class Test9 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Runnable t1=new MyThread9();
		Thread t2=new MyThread10();
		t1.start();
		t2.start();
	}

}

class MyThread9 implements Runnable{

	@Override
	public void run() {
		// TODO Auto-generated method stub
		for(int i=0;i<100;i++) {
			try {
				Thread.sleep((int)(Math.random()*1000));
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			System.out.println("hello");
		}
	}
}
class MyThread10 implements Runnable{

	@Override
	public void run(){
		// TODO Auto-generated method stub
		for(int i=0;i<100;i++) {
		
				try {
					Thread.sleep((int)(Math.random()*1000));
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
		
			System.out.println("world");
		}
	}

}
public class Test9 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Runnable t1=new MyThread9();
		Thread t3=new Thread(t1);
		Thread t2=new Thread (new MyThread10());
		t3.start();
		t2.start();
	}

消费和生产问题

public class TestProductCustomer {
	public static void main(String[] args) {
		Shop shop = new Shop();//共享资源对象
		
		Thread p = new Thread(new Product(shop),"生产者");
		Thread c = new Thread(new Customer(shop),"消费者");
		
		p.start();
		c.start();
	}
}
class Goods{
	private int id;
	public Goods(int id) {
		this.id = id;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	
}
class Shop{
	Goods goods;
	boolean flag;//标识商品是否充足
	//生产者调用的 存的方法
	public synchronized void saveGoods(Goods goods) throws InterruptedException {
		//1.判断商品是否充足
		if(flag == true) {
			System.out.println("生产者：商品充足！要等待了！");
			this.wait();//商品充足，生产者不用生产，而等待消费者买完！进入等待状态
		}
		//商品不充足！生产者生产商品，存到商场里
		System.out.println(Thread.currentThread().getName()+"生产并在商场里存放了"+goods.getId()+"件商品");
		this.goods = goods;
		flag = true;//已经有商品了！可以让消费者购买了！
		//消费者等待。。。
		this.notifyAll();//将等待队列的消费者唤醒！前来购买商品
	}
	//消费者调用的 取的方法
	public synchronized void buyGoods() throws InterruptedException {
		if(flag == false) {//没有商品了！消费者就要等待！
			System.out.println("消费者：商品不充足！要等待了！");
			this.wait();//消费者进入等待队列！等待生产者生产商品后，唤醒！
		}
		//正常购买商品
		System.out.println(Thread.currentThread().getName()+"购买了"+goods.getId()+"件商品");
		//商品买完了！标识没货了！
		this.goods = null;
		flag =false;
		//唤醒生产者去生产商品
		this.notifyAll();
	}
}
//生产者
class Product implements Runnable{
	Shop shop;//商场
	public Product(Shop shop) {
		this.shop = shop;
	}
	public void run() {
		//通过循环，生产商品存放到Shop里
		for(int i = 1;i<=30;i++) {
			try {
				//生产者线程调用存商品的方法。传一个商品对象
				this.shop.saveGoods(new Goods(i));
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}
//消费者
class Customer implements Runnable{
	Shop shop;//商场
	public Customer(Shop shop) {
		this.shop = shop;
	}
	public void run() {
		for(int i =1;i<=30;i++) {
			try {
				this.shop.buyGoods();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}