多线程(三)
2019獨角獸企業重金招聘Python工程師標準>>>
package com.ninemax.application.multithread;public class FetchMoneyTest {public static void main(String[] args) {Bank bank = new Bank();Thread t1 = new MoneyThread(bank);// 從銀行取錢Thread t2 = new MoneyThread(bank);// 從取款機取錢t1.start();t2.start();}}class Bank {private int money = 1000;public synchronized int getMoney(int number) {if (number < 0) {return -1;} else if (number > money) {return -2;} else if (money < 0) {return -3;} else {try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}money -= number;System.out.println("Left Money: " + money);return number;}}}class MoneyThread extends Thread {private Bank bank;public MoneyThread(Bank bank) {this.bank = bank;}@Overridepublic void run() {System.out.println(bank.getMoney(800));} }運行結果:
Left Money: 200 800 -2如果方法沒有加synchronized關鍵字,運行結果:
Left Money: -600 800 Left Money: -600 800上面結果是因為在第一個線程sleep的時候,第二個線程也訪問到了相同的資源,所以需要在方法上鎖,才能同步.
轉載于:https://my.oschina.net/Tsher2015/blog/682749
總結
- 上一篇: Redis模式匹配删除key
- 下一篇: [基础]iOS 可视化编程(全系列)