方法:
用format方法,语法“String.format("%.2f",数值)”用DecimalFormat的format方法用setScale方法进行四舍五入用setMaximumFractionDigits方法
方法一:String的format方法(推荐)
double f = 12345.6789;System.out.println(String.format("%.2f", f));
方法二:DecimalFormat的format方法
double f = 12345.6789;DecimalFormat df = new DecimalFormat("#.00"); System.out.println(df.format(f));
方法三:BigDecimal的setScale方法
double f = 12345.6789;BigDecimal bg = new BigDecimal(f); double f1 = bg.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue(); System.out.println(f1);
方法四:NumberFormat的setMaximumFractionDigits方法
double f = 12345.6789;NumberFormat nf = NumberFormat.getNumberInstance(); nf.setMaximumFractionDigits(2); System.out.println(nf.format(f));
完整示例代码:
import java.math.BigDecimal;import java.text.DecimalFormat;import java.text.NumberFormat;public class format {double f = 12345.6789;public void m1() {BigDecimal bg = new BigDecimal(f);double f1 = bg.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();System.out.println(f1);}/*** DecimalFormat转换最简便*/public void m2() {DecimalFormat df = new DecimalFormat("#.00");System.out.println(df.format(f));}/*** String.format打印最简便*/public void m3() {System.out.println(String.format("%.2f", f));}public void m4() {NumberFormat nf = NumberFormat.getNumberInstance();nf.setMaximumFractionDigits(2);System.out.println(nf.format(f));}public static void main(String[] args) {format f = new format();f.m1();f.m2();f.m3();f.m4();}}