java concurrent学习-简单的synchronized vs lock vs atomic
package concurrentstudy;import java.io.IOException;import java.util.*;import java.util.concurrent.BrokenBarrierException;import java.util.concurrent.CyclicBarrier;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit;import java.util.concurrent.atomic.AtomicInteger;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;public class CompareLock {public static Integer count=0;public static AtomicInteger ai = new AtomicInteger(0);public static void main(String[] args) {ExecutorService es = Executors.newFixedThreadPool(100);long start= System.currentTimeMillis();for(int i=1;i<=200000;i++){es.submit(new Runnable() {public void run() {synchronized (ExecutorService.class) {count+=1;}}});}es.shutdown();while(!es.isTerminated()){}long end= System.currentTimeMillis();System.out.println(end-start);System.out.println(count);ExecutorService es2 = Executors.newFixedThreadPool(100);count=0;final Lock lock = new ReentrantLock ();long start2= System.currentTimeMillis();for(int i=1;i<=200000;i++){es2.submit(new Runnable() {public void run() {lock.lock();count+=1;lock.unlock();}});}es2.shutdown();while(!es2.isTerminated()){}long end2= System.currentTimeMillis();System.out.println(end2-start2);System.out.println(count);ExecutorService es3 = Executors.newFixedThreadPool(100);long start3= System.currentTimeMillis();for(int i=1;i<=200000;i++){es3.submit(new Runnable() {public void run() {CompareLock.ai.incrementAndGet();}});}es3.shutdown();while(!es3.isTerminated()){}long end3= System.currentTimeMillis();System.out.println(end3-start3);System.out.println(ai);}}