package com.xiangwen.day3; import java.util.concurrent.CountDownLatch; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.atomic.AtomicBoolean; import java.util.concurrent.atomic.AtomicInteger; public class AtomicTest { public static void main(String[] args) { // AtomicBoolean atomicFlg=new AtomicBoolean(false); // boolean res=atomicFlg.compareAndSet(false,true); // System.out.println(res); // System.out.println(atomicFlg); // // AtomicInteger atomicInt=new AtomicInteger(); // boolean res2=atomicInt.compareAndSet(10,123); // System.out.println(res2); // System.out.println(atomicInt); // Integer a=0; // atomicInt.addAndGet(2); UnsafeCounter UnsafeCounter=new UnsafeCounter(); CountDownLatch c1=new CountDownLatch(200); ExecutorService executorService = Executors.newCachedThreadPool(); for(int i=0;i<200;i++){ new Thread(new ThreadTestInt(UnsafeCounter)).start(); c1.countDown(); } try { c1.await(); Thread.sleep(1000); System.out.println("=======UnsafeCounter:"+UnsafeCounter.get()); } catch (InterruptedException e) { e.printStackTrace(); } //使用线程安全的原子类 SafeCounter safeCounter=new SafeCounter(); CountDownLatch c2=new CountDownLatch(200); for(int j=0;j<200;j++){ new Thread(new ThreadTestAtomicInt(safeCounter)).start(); c2.countDown(); } try { c2.await(); Thread.sleep(1000); System.out.println("=======safeCounter:"+safeCounter.get()); } catch (InterruptedException e) { e.printStackTrace(); } } } class ThreadTestInt implements Runnable{ private UnsafeCounter unsafeCounter; public ThreadTestInt(UnsafeCounter unsafeCounter) { this.unsafeCounter = unsafeCounter; } @Override public void run() { unsafeCounter.add(); } } class ThreadTestAtomicInt implements Runnable{ private SafeCounter safeCounter; public ThreadTestAtomicInt(SafeCounter safeCounter) { this.safeCounter = safeCounter; } @Override public void run() { safeCounter.add(); } } class UnsafeCounter { public int count = 0; public void add() {//没有加同步sychronized if(count%2==0){//for循环开启200个线程,因为i++运行很快,相当于顺序运行了,这样让线程稍微休眠,等其他线程创建出来竞争cpu try { Thread.sleep(5); } catch (InterruptedException e) { e.printStackTrace(); } } count++; } public int get() { return count; } } class SafeCounter { public AtomicInteger count = new AtomicInteger(0); public void add() { if(count.get()%2==0){//for循环开启200个线程,因为i++运行很快,相当于顺序运行了,这样让线程稍微休眠,等其他线程创建出来竞争cpu try { Thread.sleep(5); } catch (InterruptedException e) { e.printStackTrace(); } } count.addAndGet(1); } public int get() { return count.get(); } }