如果输入不是3位,
如10,哪么百位是0,
1201,哪么百位是2,1就是百位以上的数了,
package com;
import java.util.Scanner;
public class EachCount {
    public static void main(String[] args) {
        CountValue a = new CountValue();
        System.out.println("请输入一个数:");
        a.count = a.valueIntKey();
        a.f();
    }
}
class CountValue {
    int count;
    int count_1, count1, count10, count100;
    void f() {
        count_1 = count / 100;
        count100 = count_1 % 10;
        count_1 /= 10;
        count10 = (count / 10) % 10;
        count1 = (count % 10) % 10;
        System.out.println("百位以上的数是 " + count_1);
        System.out.println("百位" + count100);
        System.out.println("十位是 " + count10);
        System.out.println("个位是 " + count1);
    }
    public int valueIntKey() {
        Scanner scanner = new Scanner(System.in);
        int inCount = scanner.nextInt();
        return inCount;
    }
}
结果:
请输入一个数:
12345
百位以上的数是 12
百位3
十位是 4
个位是 5
____________________
请输入一个数:
12
百位以上的数是 0
百位0
十位是 1
个位是 2
个位是 5
由于我自己也是初学者,考虑的不是很好,如果大家有什么更好的方法,可以交流一下.