java中ThreadLocalRandom的使用详解

  public int nextInt() {
    return next(32);
  }

  protected int next(int bits) {
    long oldseed, nextseed;
    AtomicLong seed = this.seed;
    do {
      oldseed = seed.get();
      nextseed = (oldseed * multiplier + addend) & mask;
    } while (!seed.compareAndSet(oldseed, nextseed));
    return (int)(nextseed >>> (48 - bits));
  }

ThreadLocalRandom.current().nextInt();

public class RandomUsage {

  public void testRandom() throws InterruptedException {
    ExecutorService executorService=Executors.newFixedThreadPool(2);
    Random random = new Random();
    List<Callable<Integer>> callables = new ArrayList<>();
    for (int i = 0; i < 1000; i++) {
      callables.add(() -> {
        return random.nextInt();
      });
      }
    executorService.invokeAll(callables);
  }

  public static void main(String[] args) throws RunnerException {
    Options opt = new OptionsBuilder()
        .include(RandomUsage.class.getSimpleName())
        // 预热5轮
        .warmupIterations(5)
        // 度量10轮
        .measurementIterations(10)
        .forks(1)
        .build();

    new Runner(opt).run();
  }
}
public class ThreadLocalRandomUsage {

  @Benchmark
  @BenchmarkMode(Mode.AverageTime)
  @OutputTimeUnit(TimeUnit.MICROSECONDS)
  public void testThreadLocalRandom() throws InterruptedException {
    ExecutorService executorService=Executors.newFixedThreadPool(2);
    List<Callable<Integer>> callables = new ArrayList<>();
    for (int i = 0; i < 1000; i++) {
      callables.add(() -> {
        return ThreadLocalRandom.current().nextInt();
      });
      }
    executorService.invokeAll(callables);
  }

  public static void main(String[] args) throws RunnerException {
    Options opt = new OptionsBuilder()
        .include(ThreadLocalRandomUsage.class.getSimpleName())
        // 预热5轮
        .warmupIterations(5)
        // 度量10轮
        .measurementIterations(10)
        .forks(1)
        .build();

    new Runner(opt).run();
  }
}