怎么用java语言编写:计算并输出一个整数各位数字之和？

public class Test {

public static void main(String[] args) {

int a = 1203;

int sum = 0;

while(a / 10 != 0){

sum += a % 10;

a = a / 10;

}sum = sum + a;

System.out.println("各位数字之和为" + sum);

}

}

testing

各位数字之和为6

import java.io.*;

public class ssss

{

public static void main(String[] args)
{

String num=null;

System.out.println("请输入一个整数,回车结束");
try

{
InputStreamReader isr=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(isr);
while((num=br.readLine())!=null&&num.length()!=0)

{
sum(num);
System.out.println("请输入一个整数,回车结束");
}

}
catch(Exception e)
{
e.printStackTrace();
}

}

public static void sum(String num)
{
int b=0;
for(int i=0;i<num.length();i++)
{
b+=Integer.parseInt(num.substring(i,i+1));
}

System.out.println("该整数各个位上数字之和为："+b);
}

}