用Java写出二分查到的代码实现

在Java中，二分查找（Binary Search）通常用于有序数组中查找特定元素。以下是二分查找算法的基本实现：

public class BinarySearch {
    public int binarySearch(int[] nums, int target) {
        if (nums == null || nums.length == 0) {
            return -1; // 数组为空
        }
        
        int left = 0;
        int right = nums.length - 1;
        
        while (left <= right) {
            int mid = left + (right - left) / 2; // 计算中间索引
            
            if (nums[mid] == target) {
                return mid; // 找到目标值，返回其索引
            } else if (nums[mid] < target) {
                left = mid + 1; // 目标大于中间值，更新左边界
            } else {
                right = mid - 1; // 目标小于中间值，更新右边界
            }
        }
        
        return -1; // 没找到目标，返回-1
    }

    // 示例
    public static void main(String[] args) {
        int[] sortedArray = {1, 3, 5, 7, 9};
        int target = 5;
        BinarySearch bs = new BinarySearch();
        int result = bs.binarySearch(sortedArray, target);
        if (result != -1) {
            System.out.println("Target " + target + " found at index " + result);
        } else {
            System.out.println("Target not found in the array");
        }
    }
}