二分查找的前提是数组是有序的，这点我们要注意，我们可以在使用二分查找的时候先对数组进行排序。下面附上代码。

class Demo14_1{	public static void main(String[] args) throws IOException{		int[] arr ={0,1,2,3,4,5};		int a = find(arr,-1);		System.out.println(a);			}	public static int find(int[] arr,int number){		if(arr == null && arr.length ==0) return -1;		if(arr.length == 1 && arr[0] == number ) return 0;				int min = 0;		int max = arr.length -1;		int mid = max/2;		while(true){			if(number > arr[mid]){				min = mid+1;				mid = (max+min)/2;			}else if(number < arr[mid]){				max = mid-1;				mid = (max+min)/2;			}else{				return mid;			}			if(max