Lock锁 Lock锁传统synchronized锁package com.sw; /** * @Author suaxi * @Date 2021/1/4 14:00 */ public class SaleTicket01 { public static void main(String[] args) { Ticket1 ticket1 = new Ticket1(); new Thread(() ->{for (int i = 0; i < 30; i++) ticket1.sale();},"A").start(); new Thread(() ->{for (int i = 0; i < 30; i++) ticket1.sale();},"B").start(); new Thread(() ->{for (int i = 0; i < 30; i++) ticket1.sale();},"C").start(); } } //synchronized锁 class Ticket1{ private int num = 30; public synchronized void sale(){ if (num>0){ System.out.println(Thread.currentThread().getName()+"卖了"+(num--)+"张票，剩余："+num); } } } Lock接口公平锁：先来后到非公平锁：可以插队（默认使用）package com.sw; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; /** * @Author suaxi * @Date 2021/1/4 11:28 */ public class SaleTicket02 { public static void main(String[] args) { Ticket ticket = new Ticket(); new Thread(() ->{for (int i = 0; i < 30; i++) ticket.sale();},"A").start(); new Thread(() ->{for (int i = 0; i < 30; i++) ticket.sale();},"B").start(); new Thread(() ->{for (int i = 0; i < 30; i++) ticket.sale();},"C").start(); } } //Lock锁 class Ticket{ private int num = 30; //1.新建重入锁 Lock lock = new ReentrantLock(); public void sale(){ lock.lock(); //2.加锁 try{ //业务代码 if (num>0){ System.out.println(Thread.currentThread().getName()+"卖了"+(num--)+"张票，剩余："+num); } }catch (Exception e){ e.printStackTrace(); }finally { lock.unlock(); //3.解锁 } } } synchronized与Lock的区别1、synchronized 是内置的Java关键字；Lock是一个Java类2、synchronized 无法判断 获取锁 的状态；Lock可以判断3、synchronized 会自动释放锁；Lock必须手动释放，如果不释放，会产生死锁问题4、synchronized 线程1（获得锁，阻塞），线程2（一直傻傻的等待）；Lock锁就不一定会一直等待下去lock.trylock()5、synchronized 可重入锁，不可中断，非公平；Lock 可重入锁，可以判断锁的状态，非公平（可自定义公平性）6、synchronized 适用于锁少量的同步代码问题；Lock 适合大量同步代码问题