用Java写一个折半查找

import java.util.Comparator;  
  
public class MyUtil {  
  
   public static <T extends Comparable<T>> int binarySearch(T[] x, T key) {  
      return binarySearch(x, 0, x.length- 1, key);  
   }  
  
   // 使用循环实现的二分查找  
   public static <T> int binarySearch(T[] x, T key, Comparator<T> comp) {  
      int low = 0;  
      int high = x.length - 1;  
      while (low <= high) {  
          int mid = (low + high) >>> 1;  
          int cmp = comp.compare(x[mid], key);  
          if (cmp < 0) {  
            low= mid + 1;  
          }  
          else if (cmp > 0) {  
            high= mid - 1;  
          }  
          else {  
            return mid;  
          }  
      }  
      return -1;  
   }  
  
   // 使用递归实现的二分查找  
   private static<T extends Comparable<T>> int binarySearch(T[] x, int low, int high, T key) {  
      if(low <= high) {  
        int mid = low + ((high -low) >> 1);  
        if(key.compareTo(x[mid])== 0) {  
           return mid;  
        }  
        else if(key.compareTo(x[mid])< 0) {  
           return binarySearch(x,low, mid - 1, key);  
        }  
        else {  
           return binarySearch(x,mid + 1, high, key);  
        }  
      }  
      return -1;  
   }  
}