@Test
    public void equalsTest(){
        //源数组
        int[] arr1={1,2,3,4,5,6,7,8,9};
        int[] arr2={1,2,3,4,5};
        int[] arr3={1,2,3,4,5,6,7,8,9};

        System.out.println("arr1与 arr2是否相同:"+Arrays.equals(arr1,arr2));
        System.out.println("arr1与 arr3是否相同:"+Arrays.equals(arr1,arr3));
    }

 @Test
    public void fillTest1(){
        //源数组有内容填充:
        int[] arr1={1,2,3,4,5,6,7,8,9};
       //填充100
        Arrays.fill(arr1,100);
        System.out.println("有内容数组填充:"+Arrays.toString(arr1));

        int[] arr2=new int[9];
        Arrays.fill(arr2,100);
        System.out.println("无内容数组填充:"+Arrays.toString(arr2));
    }

 public static void fill(int[] a, int val) {
        for (int i = 0, len = a.length; i < len; i++)
            a[i] = val;
  }

 @Test
    public void fillTest2(){
        //源数组有内容填充:
        int[] arr1={1,2,3,4,5,6,7,8,9};
        //填充100,只填充2~5 索引处的内容
        Arrays.fill(arr1,2,5,100);
        System.out.println("有内容数组2~5填充:"+Arrays.toString(arr1));

        int[] arr2=new int[9];
        Arrays.fill(arr2,2,5,100);
        System.out.println("无内容数组2~5填充:"+Arrays.toString(arr2));
    }

 public static void fill(int[] a, int fromIndex, int toIndex, int val) {
       // rangeCheck(a.length, fromIndex, toIndex); //检查范围是否合理
        for (int i = fromIndex; i < toIndex; i++)
            a[i] = val;
    }

 @Test
    public void parallelPrefixTest(){

        int[] arr={1,2,3,4,5,6,7,8,9};

        Arrays.parallelPrefix(arr, new IntBinaryOperator() {
            //left代表数组中前一个索引处的元素值，第一个元素，不进入该方法计算
            //right代表数组中当前索引处的元素值
            @Override
            public int applyAsInt(int left, int right) {
                return left*right;
            }
        });
        System.out.println("新内容为:"+Arrays.toString(arr));
    }

 @Test
    public void parallelSetAllTest(){
        int[] arr={1,2,3,4,5,6,7,8,9};
        Arrays.parallelSetAll(arr, new IntUnaryOperator() {
            @Override
            public int applyAsInt(int operand) {
                return operand*2;
            }
        });
        System.out.println("有内容的新内容为:"+Arrays.toString(arr));

         arr=new int[9];
        Arrays.parallelSetAll(arr, new IntUnaryOperator() {
            @Override
            public int applyAsInt(int operand) {
                return operand*2;
            }
        });
        System.out.println("无内容的新内容为:"+Arrays.toString(arr));
    }

 @Test
    public void setAllTest(){
        int[] arr={1,2,3,4,5,6,7,8,9};
        Arrays.setAll(arr, new IntUnaryOperator() {
            @Override
            public int applyAsInt(int operand) {
                return operand*3;
            }
        });
        System.out.println("有内容的新内容为:"+Arrays.toString(arr));

        arr=new int[9];
        Arrays.setAll(arr, new IntUnaryOperator() {
            @Override
            public int applyAsInt(int operand) {
                return operand*3;
            }
        });
        System.out.println("无内容的新内容为:"+Arrays.toString(arr));
    }

 @Test
    public void parallelSortTest1(){
        int[] arr={1,3,5,7,9,2,4,6,8};
        Arrays.parallelSort(arr);
        System.out.println("排序后的数组为:"+Arrays.toString(arr));
    }

@Test
    public void parallelSortTest2(){
        int[] arr={1,3,5,7,9,2,4,6,8};
        //只排序 3~7， 即 7,9,2,4 四个元素。 排序完为 2,4,7,9
        Arrays.parallelSort(arr,3,7);
        System.out.println("排序后的数组为:"+Arrays.toString(arr));
    }

@Test
    public void sortTest1(){
        int[] arr={1,3,5,7,9,2,4,6,8};
        Arrays.sort(arr);
        System.out.println("排序后的数组为:"+Arrays.toString(arr));
    }

@Test
    public void sortTest2(){
        int[] arr={1,3,5,7,9,2,4,6,8};
        //只排序 3~7， 即 7,9,2,4 四个元素。 排序完为 2,4,7,9
        Arrays.sort(arr,3,7);
        System.out.println("排序后的数组为:"+Arrays.toString(arr));
    }

@Test
    public void streamTest1(){
        int[] arr={1,2,3,4,5,6,7,8,9};
        //转换成流
        Arrays.stream(arr).forEach(n -> System.out.print(n));
    }

@Test
    public void streamTest2(){
        int[] arr={1,2,3,4,5,6,7,8,9};
        //将索引位置为 3~8的转换成流，不包括8索引处的元素
        Arrays.stream(arr,3,8).forEach(n -> System.out.print(n));
    }