剑指offer-把数组排成最小的数

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
public class Solution {
    public String PrintMinNumber(int [] numbers) {
         /*
        Integer[] nums = new Integer[numbers.length];
        for(int i =0;i<numbers.length;i++){
            nums[i] = numbers[i];
        }
        */
        //将基本类型转化为封装类型，lamda表达式只能推断封装类型
        Integer[] nums = Arrays.stream(numbers).boxed().toArray(Integer[]::new);
        //转化成字符串后直接比较大小即可。
        Arrays.sort(nums,(n1,n2)->{
            String s1 = "" + n1 +n2;
            String s2 = "" + n2 +n1;
            return s1.compareTo(s2);
        });
        StringBuffer sb = new StringBuffer("");
        for(int i = 0;i < nums.length;i++){
            sb.append(nums[i]);
        }
        return sb.toString();
    }
}