取一个整数a从右端开始的4～7位

 1 package com.li.FiftyAlgorthm;
 2 
 3 import java.util.Scanner;
 4 
 5 public class FS {
 6     public static void main(String[] args) {
 7         Scanner s = new Scanner(System.in);
 8         boolean is = true;
 9         System.out.print("请输入一个7位以上的正整数：");
10         long a = s.nextLong();
11         String ss = Long.toString(a);
12         char[] ch = ss.toCharArray();
13         int j = ch.length;
14         if (j < 7) {
15             System.out.println("输入错误！");
16         } else {
17             System.out.println("截取从右端开始的4～7位是：" + ch[j - 7] + ch[j - 6]
18                     + ch[j - 5] + ch[j - 4]);
19         }
20     }
21 }