java DoubleUtil floating point tool class source code

package com.util
import java.text.DecimalFormat;

public class DoubleUtil{
    /**
    * 格式化doule
    * @return
    */
    public static double formatDoubleDigit(double _dboule, int digit) {
        StringBuffer buff =  new StringBuffer("#.");
        for(int i = 0; i< digit; i++){
            buff.append("0");
        }
        DecimalFormat df = new DecimalFormat(buff.toString());
        return Double.valueOf(df.format(_dboule));
    }
}