synchronizedemo.java

java入门经典教程 java入门经典教程 java入门经典教程

// 例 4.5.2 SynchronizeDemo.java
class SaleTickets implements Runnable
{	
	private String ticketNo = "100750";  // 车票编号
	private int ticket = 1;  // 共享私有成员，编号为100750的车票数量为1
	public void run()
	{
		System.out.println(Thread.currentThread().getName()+" is saling 
			Ticket "+ticketNo);  // 当前系统正在处理订票业务
		// 下面同步代码块中的代码为关键代码，用syschronized关键字来标识
		synchronized(this)  
		{
			if(ticket>0)
{
		 		try{   // 休眠0-1000毫秒，用来模拟网络延迟
					Thread.sleep((int)(Math.random()*1000));
				}catch(InterruptedException e){}
				ticket=ticket-1;     // 修改车票数据库的信息
				System.out.println("ticket is saled by 
				"+Thread.currentThread().getName()+", amount is: "+ticket);
				// 显示当前该车票的预订情况
			}
		else 
System.out.println("Sorry "+Thread.currentThread().getName()+",  
				Ticket "+ticketNo+" is saled");   // 显示该车票已被预订
		}
	}
}
class SynchronizeDemo
{
	public static void main(String[] args)
	{
		SaleTickets m = new SaleTickets();
		Thread t1 = new Thread(m,"System 1"); 
		Thread t2 = new Thread(m,"System 2");
		t1.start();
		t2.start();
	}
}