Java保留两位小数

采用四舍五入的方式 ： 该方式来自网络

import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.text.NumberFormat;

public class format {
double f = 111231.5585;
public void m1() {
BigDecimal bg = new BigDecimal(f);
double f1 = bg.setScale(2, BigDecimal.ROUND_HALF_UP).doubleva lue();
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();
}
}

结果：
111231.56
111231.56
111231.56
111,231.56

采用非四舍五入的方式 ：

[java]
public static void main(String[] args) {
double finalMoney = 27.989;
System.out.println(finalMoney);
DecimalFormat formater = new DecimalFormat();
formater.setMaximumFractionDigits(2);
formater.setGroupingSize(0);
formater.setRoundingMode(RoundingMode.FLOOR);
System.out.println(formater.format(finalMoney));
}

public static void main(String[] args) {
double finalMoney = 27.989;
System.out.println(finalMoney);
DecimalFormat formater = new DecimalFormat();
formater.setMaximumFractionDigits(2);
formater.setGroupingSize(0);
formater.setRoundingMode(RoundingMode.FLOOR);
System.out.println(formater.format(finalMoney));
}
结果

27.989
27.98