算法对于大家来说应该已经见过写过不少了吧，下面介绍一种常见的算法-----二分查找法
使用泛型实现二分查找
public class Test{
  public static < T  extends Comparable < ? super T>> int binarySearch(T [] array,T key){
        int low = 0;
        int high = array.length-1;
        while(low <= high){
            int mid = (low + high)/2;
            if(array[mid].compareTo(key)< 0){
                low = mid + 1;
            }else if(array[mid].compareTo(key)>0){
                high = mid - 1;
            }else{
                return mid;
            }
        }
        return -1;
    }
     public static void main(String args[]){
        Integer  a[]={1,2,3,4,5,6,7,8,9};
        int k=binarySearch(a,7);
        System.out.println("k="+k);
    }
}