java多线程篇

1：需求

创建两个线程，一个线程往集合中添加元素，另个线程监控当集合元素个数达到某个值抛出异常

2：代码一

public class ListAdd1 {

	private volatile static List list = new ArrayList();	
	
	public void add(){
		list.add("1");
	}
	public int size(){
		return list.size();
	}
	
	public static void main(String[] args) {
		
		final ListAdd1 list1 = new ListAdd1();
		
		Thread t1 = new Thread(new Runnable() {
			@Override
			public void run() {
				try {
					for(int i = 0; i <10; i++){
						list1.add();
						System.out.println("当前线程：" + Thread.currentThread().getName() + "添加了一个元素..");
						Thread.sleep(500);
					}	
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}, "t1");
		
		Thread t2 = new Thread(new Runnable() {
			@Override
			public void run() {
				while(true){
					if(list1.size() == 5){
						System.out.println("当前线程收到通知：" + Thread.currentThread().getName() + " list size = 5 线程停止..");
						throw new RuntimeException();
					}
				}
			}
		}, "t2");		
		
		t1.start();
		t2.start();
	}
	
	
}

3：代码二

public class ListAdd2 {
	private volatile static List list = new ArrayList();	
	
	public void add(){
		list.add("2");
	}
	public int size(){
		return list.size();
	}
	
	public static void main(String[] args) {
		
		final ListAdd2 list2 = new ListAdd2();
		final Object lock = new Object();
		Thread t1 = new Thread(new Runnable() {
			@Override
			public void run() {
				try {
					synchronized (lock) {
						System.out.println("t1启动..");
						for(int i = 0; i <10; i++){
							list2.add();
							System.out.println("当前线程：" + Thread.currentThread().getName() + "添加了一个元素..");
							Thread.sleep(500);
							if(list2.size() == 5){
								System.out.println("已经发出通知..");
								lock.notify();
							}
						}						
					}
				} catch (InterruptedException e) {
					e.printStackTrace();
				}

			}
		}, "t1");
		
		Thread t2 = new Thread(new Runnable() {
			@Override
			public void run() {
				synchronized (lock) {
					System.out.println("t2启动..");
					if(list2.size() != 5){
						try {
							lock.wait();
						} catch (InterruptedException e) {
							e.printStackTrace();
						}
					}
					System.out.println("当前线程：" + Thread.currentThread().getName() + "收到通知线程停止..");
					throw new RuntimeException();
				}
			}
		}, "t2");	
		t2.start();
		t1.start();
		
	}
	
}