Java中CompareTo()方法

import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner cin=new Scanner(System.in);

        String s1="123";
        String s2="132";
        String s3="123";
        System.out.println(s1.compareTo(s2)); // -1  负值说明s1小余s2
        System.out.println(s2.compareTo(s3)); // 1
        System.out.println(s1.compareTo(s3)); // 1
        return;
    }

}