nanoTime对volatile 测试的一种写法

时间：2014-05-16 00:41:55 收藏：0 阅读：471

今天脑筋有点搭牢，想了半天才看出为什么以下两段代码效果是相同的。。。

第一种好处是可以直接批量复制黏贴system.out, 不用改什么东西

private static long i;
private volatile static long vt;
private static final int TEST_SIZE = 10000000;

long time = System.nanoTime();
for (int n = 0; n < TEST_SIZE; n++)
    vt = System.currentTimeMillis();
System.out.println(-time + (time = System.nanoTime()));<br>
for (int n = 0; n < TEST_SIZE; n++)
    i = System.currentTimeMillis();
System.out.println(-time + (time = System.nanoTime()));

这种每次要在循环头上重置nanoTime

<span>private 
static long i;</span><br><span>private 
volatile static long vt;</span><br><span>private 
static final int TEST_SIZE = 10000000;</span><br><br>long 
time = System.nanoTime();
for (int n = 0; n < TEST_SIZE; n++) {
            vt = System.currentTimeMillis();
}
System.out.println((System.nanoTime() - time));
 
time = System.nanoTime();
for (int n = 0; n < TEST_SIZE; n++) {
      i = System.currentTimeMillis();
}
System.out.println((System.nanoTime() - time));

nanoTime对volatile 测试的一种写法,布布扣,bubuko.com

原文：http://www.cnblogs.com/zhukunrong/p/3730106.html