Java中Double类型的四舍五入

import java.math.BigDecimal;
import java.util.Scanner;

public class Main {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Main m = new Main();
}

public Main(){
System.out.println("请输入需小数点后2位进行要四舍五入的小数：（如3.254）");
Scanner sc = new Scanner(System.in);
double d = sc.nextDouble();
BigDecimal b = new BigDecimal(d );
double f1 = b.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
System.out.println("四舍五入后为："+f1);

}

}