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  • nanoTime对volatile 测试的一种写法

    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()));
    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

    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((System.nanoTime() - time)); time = System.nanoTime(); for (int n = 0; n < TEST_SIZE; n++) { i = System.currentTimeMillis(); } System.out.println((System.nanoTime() - time));

      

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  • 原文地址:https://www.cnblogs.com/zhukunrong/p/3730106.html
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