这里分别使用有锁和无锁两种方式,对一个数值进行增加,一直增加到100000,然后输出使用时间的长短。
1 import java.util.concurrent.ExecutorService; 2 import java.util.concurrent.Executors; 3 import java.util.concurrent.TimeUnit; 4 import java.util.concurrent.atomic.AtomicInteger; 5 6 public class TestAtomic { 7 8 // 设置线程数量 9 private static int N = 1000; 10 // 设置最大值 11 private static int M = 1000000; 12 13 /** 14 * 无锁方法 15 * 16 * @throws InterruptedException 17 */ 18 private static void atomicMethod() throws InterruptedException { 19 AtomicRun atomicRun = new AtomicRun(); 20 AtomicRun.endValue = M; 21 22 ExecutorService service = Executors.newFixedThreadPool(N); 23 // 开始时间 24 long starttime = System.currentTimeMillis(); 25 for (int i = 0; i < N; i++) { 26 service.submit(atomicRun); 27 } 28 service.shutdown(); 29 service.awaitTermination(Integer.MAX_VALUE, TimeUnit.MILLISECONDS); 30 // 结束时间 31 long endTime = System.currentTimeMillis(); 32 System.out.println("无锁线程数量为 : " + N + " 开始时间为 : " + starttime 33 + " 结束时间为 : " + endTime + " 耗费时间为 : " + (endTime - starttime) 34 + "ms" + " value:" + AtomicRun.atomicInteger); 35 } 36 37 /** 38 * 加锁方法 39 * 40 * @throws InterruptedException 41 */ 42 private static void synMethod() throws InterruptedException { 43 SynRun synRun = new SynRun(); 44 SynRun.endValue = M; 45 46 ExecutorService service = Executors.newFixedThreadPool(N); 47 long starttime = System.currentTimeMillis(); 48 for (int i = 0; i < N; i++) { 49 service.submit(synRun); 50 } 51 service.shutdown(); 52 service.awaitTermination(Integer.MAX_VALUE, TimeUnit.SECONDS); 53 long endTime = System.currentTimeMillis(); 54 System.out.println("有锁线程数量为 : " + N + " 开始时间为 : " + starttime 55 + " 结束时间为 : " + endTime + " 耗费时间为 : " + (endTime - starttime) 56 + "ms" + " value:" + AtomicRun.atomicInteger); 57 } 58 59 public static void main(String[] args) throws InterruptedException { 60 System.out.println("当线程数量为 : " + N + "时:"); 61 atomicMethod(); 62 synMethod(); 63 } 64 } 65 66 /** 67 * 68 * @author 秦孔祥 69 * 70 */ 71 class AtomicRun implements Runnable { 72 73 protected static AtomicInteger atomicInteger = new AtomicInteger(); 74 protected static int endValue; 75 76 @Override 77 public void run() { 78 int startValue = atomicInteger.get(); 79 while (startValue < endValue) { 80 startValue = atomicInteger.incrementAndGet(); 81 } 82 } 83 } 84 85 class SynRun implements Runnable { 86 87 protected static int startValue; 88 protected static int endValue; 89 90 @Override 91 public void run() { 92 while (startValue < endValue) { 93 addValue(); 94 } 95 } 96 97 private synchronized void addValue() { 98 startValue++; 99 } 100 }