java變量讀寫效率測試

時間 2019-11-12

標籤 java 變量讀寫效率測試欄目 Java 简体版

原文原文鏈接

主要測試全局變量、局部變量、volatile變量、原子變量的讀寫效率，源碼以下：oop

public class GloableVarientTest {
private long temp = 0;測試

   public void test() {
       long loop = Integer.MAX_VALUE;
       long start = System.currentTimeMillis();
       for (long i = 0; i < loop; i++) {
           temp += i;
       }
       long end = System.currentTimeMillis();
       System.out.println(end - start);
   }atom

   public void testLocal() {
       long loop = Integer.MAX_VALUE;
       long temp = 0;
       long start = System.currentTimeMillis();
       for (long i = 0; i < loop; i++) {
           temp += i;
       }
       long end = System.currentTimeMillis();
       System.out.println(end - start);
   }源碼

private volatile long volatileTemp = 0;class

   public void testVolatile() {
       long loop = Integer.MAX_VALUE;
       long start = System.currentTimeMillis();
       for (long i = 0; i < loop; i++) {
           volatileTemp += i;
       }
       long end = System.currentTimeMillis();
       System.out.println(end - start);
   }test

   public void testAtomic() {
       AtomicLong atomicTemp = new AtomicLong(0);
       long loop = Integer.MAX_VALUE;
       long start = System.currentTimeMillis();
       for (long i = 0; i < loop; i++) {
           atomicTemp.addAndGet(i);
       }
       long end = System.currentTimeMillis();
       System.out.println(end - start);
   }效率

   public static void main(String[] args) {
       GloableVarientTest gv = new GloableVarientTest();
       gv.test();
       gv.testLocal();
       gv.testVolatile();
       gv.testAtomic();
   }
}變量

讀寫效率測試結果：局部變量 > 全局變量 >>> volatile變量 ≈ 原子變量im