java常用函数(5)

控制小数点的几个常用方法

import java.text.DecimalFormat;

public class NumberUtil {

public static double decimalFormatD(int num, double d){
String format = "0.";
String result = "";
double db;

for(int i=0;i<num;i++)
format = format.concat("0");

DecimalFormat decimal = new DecimalFormat(format);
result = decimal.format(d);
db = Double.parseDouble(result);

return db;
}

public static float decimalFormatF(int num, float f){
String format = "0.";
String result = "";
float fl;

for(int i=0;i<num;i++)
format = format.concat("0");

DecimalFormat decimal = new DecimalFormat(format);
result = decimal.format(f);
fl = Float.parseFloat(result);

return fl;
}

public static String doubleToString(double f){
String s = "";
double a = 0;

while(f >= 1) {

a = f%((double)10);

s = String.valueOf((int)a) + s;
f=(f - a)/10;
}
return s;
}
}