Java多线程——线程同步

package Demo1; /** * 经典线程同步问题---银行取钱问题 * Created by Petty on 2017/4/10. */ /** * Account类 */ class Account{ //封装账户编号、账户余额两个成员变量 private String acccountNo; private double balance; public Account(){} public Account(String accountNo,double balance){ this.acccountNo=accountNo; this.balance=balance; } public void setAcccountNo(String acccountNo){ this.acccountNo = acccountNo; } public String getAcccountNo(){ return this.acccountNo; } public void setBalance(double balance){ this.balance=balance; } public double getBalance(){ return this.balance; } } public class Thread_2 extends Thread{ //声明用户账户 private Account account; //当前取钱线程希望取的金额 private double drawAmount; public Thread_2(String name,Account account,double drawAmount){ super(name); this.account=account; this.drawAmount=drawAmount; } public void run() { //使用account作为同步监视器，任何线程进入下面代码块之前， // 必须先对account账户锁定---其他程无法获得锁，也无法修改它 synchronized (account) { //账户金额大于取钱金额 if (account.getBalance() >= drawAmount) { System.out.println(getName() + "取钱成功！吐出钞票" + drawAmount); try { Thread.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); } //修改金额 account.setBalance(account.getBalance() - drawAmount); System.out.println("账户编号："+account.getAcccountNo()+ "的余额为" + account.getBalance()); } else { System.out.println(getName() + "取钱失败！余额不足！"); } } } public static void main(String[] args){ //创建一个账户 Account account=new Account("123456789",1000); //创建两个线程模拟对同一个账户取钱 Thread_2 td1=new Thread_2("张三",account,800); td1.start(); Thread_2 td2=new Thread_2("李四",account,800); td2.start(); } }
           

运行结果：

张三取钱成功！吐出钞票800.0
账户编号：123456789的余额为200.0
李四取钱失败！余额不足！