java线程学习5——线程同步之同步方法

public class Account

{

/**

* 账户号

*/

private String accountNo;

/**

* 账户余额

*/

private double balance;

public Account()

{

super();

}

public Account(String accountNo, double balance)

{

super();

this.accountNo = accountNo;

this.balance = balance;

}

@Override

public int hashCode()

{

return accountNo.hashCode();

}

@Override

public boolean equals(Object obj)

{

if (null != obj && obj.getClass() == Account.class)

{

Account target = (Account) obj;

return target.accountNo.equals(accountNo);

}

return false;

}

/**

* 同步方法，同步方法的监视器是this，同步方法可以将该类变为线程安全的类

* 任何时候只有一个线程获得对Account对象的锁定，然后进入draw方法进行取钱

*/

public synchronized void draw(double drawAmount)

{

if (balance >= drawAmount)

{

System.out.println(Thread.currentThread().getName() + "取出钞票成功" + drawAmount);

balance -= drawAmount;

System.out.println("余额为" + balance);

}

else

{

System.out.println("余额不足");

}

}

/********************** 只提供Getters，不提供Setters，确保安全 ************************/

public String getAccountNo()

{

return accountNo;

}

public double getBalance()

{

return balance;

}

}





public class DrawThread extends Thread

{

/**

* 模拟账户

*/

private Account ac;

/**

* 当前取钱线程希望取得的钱数

*/

private double drawAmount;

public DrawThread(String name, Account ac, double drawAmount)

{

super(name);

this.ac = ac;

this.drawAmount = drawAmount;

}

@Override

public void run()

{

ac.draw(drawAmount);

}

}



public class Test

{

public static void main(String[] args)

{

Account ac = new Account("00000001", 1000);

Thread t1 = new Thread(new DrawThread("Lily", ac, 800));

Thread t2 = new Thread(new DrawThread("Tom", ac, 800));

t1.start();

t2.start();

}

}