济南市个人网站制作,工作室需要营业执照吗,长沙外贸建站哪里好,厦门网站制作开发收费为什么80%的码农都做不了架构师#xff1f; ReentrantLock重入锁简单理解就是对同一个线程而言#xff0c;它可以重复的获取锁。例如这个线程可以连续获取两次锁#xff0c;但是释放锁的次数也一定要是两次 Lock locknew ReentrantLock(true);//公平锁 Lock … 为什么80%的码农都做不了架构师 ReentrantLock重入锁简单理解就是对同一个线程而言它可以重复的获取锁。例如这个线程可以连续获取两次锁但是释放锁的次数也一定要是两次 Lock locknew ReentrantLock(true);//公平锁 Lock locknew ReentrantLock(false);//非公平锁 公平锁指的是线程获取锁的顺序是按照加锁顺序来的而非公平锁指的是抢锁机制先lock的线程不一定先获得锁。Java的synchronized关键字就是非公平锁 package com.example.web.controller;import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;RestController
public class ThreadController {//测试每次请求是否重新初始化int single 0;private ReentrantLock lock new ReentrantLock();private ReentrantReadWriteLock lockRW new ReentrantReadWriteLock();//设置程序进入等待状态private Condition condition lock.newCondition();RequestMapping(thread)public int test() {//练习锁机制开启几个线程for (int i 0; i 5; i) {new Thread(() - {try {lock.lock();//此处测试线程等待和线程唤醒System.out.println(线程进入等待状态);condition.await();thread();} catch (Exception ex) {} finally {lock.unlock();}}).start();}single;System.out.println(single);return single;}//写一个方法用来唤醒线程RequestMapping(/thread/signal)public void signal() {lock.lock();condition.signal();lock.unlock();System.out.println(线程已被唤醒);}//写一个方法用来多线程调用public void thread() throws Exception {//写个循环用来多线程干扰for (int i 0; i 5; i) {System.out.println(线程 i : Thread.currentThread().getName());//得稍微耗时一下才行Thread.sleep(50);}}} private ReentrantReadWriteLock lockRW new ReentrantReadWriteLock();//读写锁 Lock类有读锁和写锁读读共享写写互斥读写互斥 参考链接https://www.cnblogs.com/-new/p/7256297.html java原子类使用的就是原子锁核心方法就是compareAndSet也就是常说的CAS用来对比更新写一段伪代码current会和实际值对比如果相同则更新成next值否则继续循环。 public final int incrementAndGet() {for (; ; ) {//获取当前值int current get();//设置期望值int next current 1;//调用Native方法compareAndSet执行CAS操作if (compareAndSet(current, next))//成功后才会返回期望值否则无线循环return next;}
} 讲解自旋锁等相关知识 https://blog.csdn.net/qq_34337272/article/details/81252853 https://mp.weixin.qq.com/s?__bizMzg2OTA0Njk0OAmid2247484911amp;idx1amp;sn1d53616437f50b353e33edad6fda2e4fsource41#wechat_redirect 各种锁介绍https://www.cnblogs.com/lzh-blogs/p/7477157.html 转载于:https://my.oschina.net/uwith/blog/3045525
