Question

Java实现数字的四舍五入并返回指定小数位数

Answer 1

import java.math.RoundingMode;import java.text.NumberFormat;class T { public static void main(String[] args) { System.out.println(function2(123.455, 2)); System.out.println(function2(123.449, 2)); System.out.println(function2(123.44, 3)); System.out.println(function2(123.4455, 3)); System.out.println(function2(123.4499, 3)); System.out.println(function2(123.9, 0)); } public static double function2(double value, int decimalPlaces) { NumberFormat nf = NumberFormat.getNumberInstance(); nf.setRoundingMode(RoundingMode.HALF_UP); // 四舍五入 nf.setMaximumFractionDigits(decimalPlaces); nf.setMinimumFractionDigits(decimalPlaces); return Double.valueOf(nf.format(value)); }}
输出结果
123.46
123.45
123.44
123.446
123.45
124.0