Java中四舍五入保留小数点后七位

package lianxi;

import java.text.DecimalFormat;

import java.util.Scanner;

public class Yuan {

public static void main(String[] args){
final double m=3.14159265358979323;
@SuppressWarnings("resource")
Scanner sc=new Scanner(System.in);
int r=sc.nextInt();
double s=m*r*r;
DecimalFormat df=new DecimalFormat("#.0000000");
System.out.println(df.format(s));

}

}