Java多线程协调控制之wait&notifyAll

最近在复习Java基础，看到多线程这块顺便写写多线程的协调控制程序。

需求：假设系统中有两个线程分别代表取款者和存款者，现在系统的要求是存款者和取款者不断的重复存、取款操作，

并且要求每当有存款者将钱存入指定账户中时，取款者就立即取出这笔钱，即不允许存款者连续两次存钱，也不允许

取款者两次取钱。

下面代码实现：

1.首先是账户Account类；

package com.xjtu.cruise.soft.thread;

public class Account {

	/**
	 * @author Cruise
	 * @param args
	 */
	private String accountNo;
	//标识账户是否还有存款的
	private boolean flag = false;
	private double balance;

	public Account(){}
	public Account(String accountNo, double balance) {
		this.accountNo = accountNo;
		this.balance = balance;
	}

	public double getBalance(){
		return balance;
	}
	public synchronized void draw(double drawAmount) {
		try {
			if (!flag) {  //如果账户没钱
				wait();  //阻塞当前的方法，并释放同步锁（这里就是this，也就是调用此方法的对象）
			} else {
				System.out.println("线程：" + Thread.currentThread().getName()
						+ "取款" + drawAmount);
				balance -= drawAmount;
				System.out.println("账户余额：" + balance);
				flag = false;
				notifyAll();  //唤醒等待此同步锁的所有线程
			}
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

	public synchronized void deposit(double depositAmount) {

		try{
			if(flag){ //如果账户有存入的钱
				wait();
			}else{
				System.out.println("线程："+ Thread.currentThread().getName()+"存款"+depositAmount);
				balance += depositAmount;
				System.out.println("账户余额：" + balance);
				flag = true;
				notifyAll();
			}
		}catch(InterruptedException e){
			e.printStackTrace();
		}
	}

}

2.接下来是存取款线程类（DrawThread,DepositThread)

package com.xjtu.cruise.soft.thread;

public class DepositThread extends Thread {

	private Account account;
	private double depositAmount;

	public DepositThread(String name, Account account, double depositAmount) {
		super(name);
		this.account = account;
		this.depositAmount = depositAmount;
	}

	public void run(){
		for(int i=0; i<100; i++){
//			System.out.println("线程：" + Thread.currentThread().getName()+"执行存款操作。");
			account.deposit(depositAmount);
		}
	}
}

package com.xjtu.cruise.soft.thread;

public class DrawThread extends Thread {
/**
     * @author Cruise
     * @param args
     */
	private Account account;
	private double drawAmount;

	public DrawThread(String name, Account account, double drawAmount) {
		super(name);
		this.account = account;
		this.drawAmount = drawAmount;
	}

	public void run(){
		for(int i=0; i<100; i++){
//			System.out.println("线程：" + Thread.currentThread().getName()+"执行取钱操作。");
			account.draw(drawAmount);
		}
	}
}

3.奉上测试类TestDraw

package com.xjtu.cruise.soft.thread;

public class TestDraw {

	/**
	 * @author Cruise
	 * @param args
	 */
	public static void main(String[] args) {
		Account account = new Account("123", 0);
		new DrawThread("取钱者", account, 800).start();
		new DepositThread("存款者甲",account, 800).start();
		new DepositThread("存款者乙",account, 800).start();

	}

}

OK， 一个线程协调控制的Demo完成。