看了评论大佬们后 自己尝试了一下 public class MyTest { public static void main(String[] args) { Bank bank = new Bank(); bank.setMoney(0); bank.setFlag(false); new Thread(()->{ for (int i = 0; i < 5; i++) { bank.get_(100); } }).start(); new Thread(()->{ for (int i = 0; i < 10; i++) { bank.save_(50); } }).start(); } }