Arrays提供了一个方便查询的方法 ：Arrays.binarySearch（）；

public static void main(String[] args) { // TODO Auto-generated method stub String[] arrays = new String[]{"a","b","c","d","e","fff","g","h","i","j",}; int positon = Arrays.binarySearch(arrays, "fff"); System.out.println("position is:"+positon); }

测试结果：

position is:5 这个方法也是用的二分法实现的：

public static int binarySearch(char[] array, int startIndex, int endIndex, char value) { checkBinarySearchBounds(startIndex, endIndex, array.length); int lo = startIndex; int hi = endIndex - 1; while (lo <= hi) { int mid = (lo + hi) >>> 1;//无符号右移 char midVal = array[mid]; if (midVal < value) { lo = mid + 1; } else if (midVal > value) { hi = mid - 1; } else { return mid; // value found } } return ~lo; // value not present } 转载：http://blog.csdn.net/mattdong0106/article/details/22676807