二分查找 （java实现）

package com.li.test01;import java.util.Scanner;/** *  * @author lixiang * */public class BinarySearch {    //存在返回数组下表，不存在返回-1    //递归实现    public static int binarySearch(int key, int[] array, int low ,int high) {        int mid = low + (high - low) / 2;        if(key < array[low] || key > array[high] || low > high){            return -1;        }                if(key < array[mid]) {          return binarySearch(key, array,low,mid-1);        }        else if(key > array[mid]) {            return binarySearch(key, array, mid+1, high);        }        else {            return mid;        }    }        //非递归实现    public static int binarySearch(int key, int[] array) {        int low = 0;        int high = array.length - 1 ;                while(low <= high) {            int mid = low + (high - low) / 2;            if(key < array[mid]){                high = mid - 1;            }             else if(key > array[mid]) {                low = mid + 1;            }            else {                return mid;            }        }        return -1;    }        public static void main(String[] args) {        Scanner in = new Scanner(System.in);        System.out.println("输入一串有序整数（以逗号分隔） : "); //要查找的数组必须是有序的        int[] intArr = readInts(in.nextLine());//        Arrays.sort(intArr); //使输入int[]有序        while(true) {            System.out.println("输入要查找数字 : ");            System.out.println(binarySearch(Integer.valueOf(in.nextLine()), intArr, 0, intArr.length-1));        }    }        private static int[] readInts(String str){        String[] strArr = str.split(",");        int[] intArr = new int[strArr.length];        for (int i = 0 ; i < strArr.length; i++) {            intArr[i] = Integer.valueOf(strArr[i]);        }        return intArr;    }}