java中求2+22+222+2222+22222.........

package excise;
import java.util.Scanner;

public class Test2 {
public  static  void main(String args[]){
Scanner s=new Scanner(System.in);
System.out.println("请输入第一个数，累加的数");
int m=s.nextInt();
System.out.println("请输入第二个数，累加的次数");
int n=s.nextInt();
caculate(m, n);

}

public  static void   caculate(int m,int n){
int i=1;
long sum=0;
long j=0;
while(i<=n){
j=j+m;
sum=sum+j;
m=m*10;
++i;
}
System.out.println("计算后的值是："+sum);
}

}