设计两个个线程模拟存取款操作，其中一个线程每次随机存1~1000元钱，另外一个线程取1－1000元钱，如果余额不足，则取款失败，提示余额不足。写出程序（考虑并发问题）。

import java.util.Random;

public class Bank {

        private float account;

        public Bank(float money) {
            this.account = money;
        }
        public synchronized float getAccount(){
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return account;
        }
        public synchronized void deposit(float money){
            account+=money;

        }
        public synchronized void drawMoney(float money) throws Exception {
            if (account < money) {
                throw new Exception("余额不足");
            }
            account -= money;
        }
    }

    class UserA extends Thread{
        private Bank bank;
        private float money;
        public UserA(Bank b,float m){
            bank=b;
            money=m;
        }
        public void run(){
            System.out.println("账户存款数额为："+bank.getAccount()+"元");
            System.out.println("用户A存了"+money+"元" );
            try{
                bank.deposit(money);
            }
            catch(Exception e){ }
            System.out.println("余额为："+bank.getAccount()+"元");
        }
    }

    class UserB extends Thread{
        private Bank bank;
        private float money;
        public UserB(Bank b,float m){
            bank=b;
            money=m;
        }
        public void run(){
            System.out.println("账户存款数额为："+bank.getAccount()+"元");
            System.out.println("用户B想取"+money+"元");
            if((bank.getAccount()-money)>0){
                System.out.println("用户B取出了"+money+"元" );
            }
            try{
                bank.drawMoney(money);
                System.out.println("余额为："+bank.getAccount()+"元");
            }
            catch(Exception e){
                System.out.println(e.getMessage());
            }

        }
    }
    class TestBank {
        public static void main(String[] args) {
            Random r=new Random();

            float f1=r.nextInt(1000)+1;
            float f2=r.nextInt(1000)+1;

            Bank a=new Bank(0);
            UserA userA=new UserA(a,f1);
            UserB userB=new UserB(a,f2);
            userA.start();

            try {
                userA.join();
            } catch (InterruptedException e) {
                userB.start();
            }
            System.out.println("==================");
            userB.start();
            try {
                userB.join();
            } catch (InterruptedException e) {
                userA.start();
            }
        }

}

 运行结果：任意随机