Java Arrays类方法

1:概述

主要谈一谈 Java使用fork/koin类 实现的并发排序 以及对于Stream流的支持的splitetor

• mismatch()   ->  寻找两个数组 第一次出现数据不一致的下标
• parallelPrefix() -> 对数组进行,累加求和
• parallelSetAll() -> 对数组进行置数,
• parallelSort()   -> 并行排序
• Spliterator() -> 对数组进行切分(切分后的数据为所有的数据的组合)
  • 奇数 x/2+1     11->6
  • 偶数  x/2    10 ==>5

public class Use_Arrays {

    @Test
    public void test_mismatch() {
        int []x =new int[] {1,2,3,4};
        int []y =new int[] {1,3,4,5};
        int index = Arrays.mismatch(x, y);
        System.out.println(index);
    }

    @Test
    public void test_parallelPrefix() {
        int []x =new int[] {1,2,3,4};
        //f2=f1+f2
        //f3=f2+f3
        Arrays.parallelPrefix(x, (k,v)->k+v);
        System.out.println(Arrays.toString(x));

        // 实现1-100累加求和
        int []y =new int[100];
        Arrays.parallelSetAll(y, k->k=1);
        Arrays.parallelPrefix(y, (k,v)->k+v);
        System.out.println(Arrays.toString(y));

    }
    @Test
    public void test_parallelSetAll() {
        int []x =new int[100];
        x[0]=1;
        Arrays.parallelSetAll(x, y->y+1);
        System.out.println(Arrays.toString(x));
    }

    @Test
    public void test_parallSort() {
          IntStream stream = new Random().ints(0, 1000).limit(1000);
          int[] array = stream.toArray();
          System.out.println(Arrays.toString(array));
          Arrays.parallelSort(array);
          System.out.println(Arrays.toString(array));
    }

    @Test
    public void test_spliterator() {
        int []x =new int[11];
        Arrays.parallelSetAll(x, k->k+=1);
        System.out.println(Arrays.toString(x));

        Spliterator.OfInt int0_100 = Arrays.spliterator(x);

        int [] y=new int[(int) int0_100.estimateSize()];
        int i=0;
        System.out.println(int0_100.estimateSize());
        System.out.println(int0_100.characteristics());
        System.out.println(int0_100.getExactSizeIfKnown());

        //spliterator.forEachRemaining((int k)->System.out.println(k));

        OfInt int1_50 = int0_100.trySplit();
        OfInt int2_25 = int1_50.trySplit();
        int0_100.forEachRemaining((int k)->System.out.print(k+" "));
        System.out.println();
        int1_50.forEachRemaining((int k)->System.out.print(k+" "));
        System.out.println();
        int2_25.forEachRemaining((int k)->System.out.print(k+" "));
    }
}

2:使用Spliterator实现并行输出

    @Test
    public void definied_Sort() {
         IntStream stream = new Random().ints(0, 100).limit(100);
         int[] array = stream.toArray();
         Arrays.sort(array);
         final int NUMS=3;// 切分的次数

         ExecutorService thread_pool = Executors.newFixedThreadPool(10);

         Spliterator.OfInt cut1 = Arrays.spliterator(array);
         while(!thread_pool.isTerminated()) {
             thread_pool.submit(()->{
                    OfInt split = cut1.trySplit();
                     thread_pool.shutdown();
                 split.forEachRemaining((int k)->System.out.print(k+" "));
                 System.out.println();
             });
         }
    }