java二分法如何找寻数组的位置

package com.study.collection;

import java.util.Arrays;

/**

 * @auth zhangmj

 * @date 2019/2/12 9:14

 */

public class ExampleList<T> {

    public static void main(String[] args) {

        int[] intArray = {0,1,2,10,15,20,25,29,31,36,39,40,42,43,46,50,55,60,63,66,70};

        int num =2;

        int[] resultArray = getPostionByTwoPoint(intArray, num);

        System.out.println(Arrays.toString(resultArray));

    }

    private static int[] getPostionByTwoPoint(int[] intArray, int num) {

        // 判断

        if(intArray == null || intArray.length == 0){

            throw new RuntimeException("数组不能为空");

        }

        // 定义最小和区间

        if(intArray[0] > num || intArray[intArray.length - 1] < num){

            throw new RuntimeException("不在数组范围之内");

        }

        int middle = 0;

        int low = 0;

        int high = intArray.length - 1;

        // 定义首尾特殊的情况

        if(intArray[low] == num){

            int[] resultArray = {low, low};

            return resultArray;

        }else if(intArray[high] == num){

            int[] resultArray = {high, high};

            return resultArray;

        }

        int i = 1;

        // 数在中间的情况

        while(low < high){

            System.out.println("查找第 " + i + " 次");

            middle = (low + high + 1)/2;

            if(intArray[middle] == num){

                int[] resultArray = {middle, middle};

                return resultArray;

            }else if(intArray[middle] > num){

                // num 在 low 和 middle 之间

                int previous = middle - 1;

                if(previous > low  && intArray[previous] < num){

                    int[] resultArray = {previous, middle};

                    return resultArray;

                }

                high = middle;

            }else if(intArray[middle] < num){

                int latter = middle + 1;

                if(latter < high  && intArray[latter] > num){

                    int[] resultArray = {middle, latter};

                    return resultArray;

                }

                low = middle;

            }

            i++;

        }

        throw new RuntimeException("定位异常");

    }

}