java 截取小数位数方法实例。

1.
java.text.NumberFormat formater = java.text.DecimalFormat.getInstance();
formater.setMaximumFractionDigits(2);
formater.setMinimumFractionDigits(2);
System.out.println(formater.format(3.1415927));;

在formater.setMaximumFractionDigits(2);后面加上
formater.setMinimumFractionDigits(2);就不会截掉最后一个0了

2.
float avprice = 234.5678f;
java.text.DecimalFormat df =new java.text.DecimalFormat(“#.00″);
String aveprice=df.format(avprice);
System.out.println(aveprice); //234.56
写#的是有值就写值，没值就不写
写0的是有值就写值，没值就写0
3.
Double num11 = Double.parseDouble(num1);
Double num22 = Double.parseDouble(num2);
String res = null;

DecimalFormat df=new DecimalFormat(“#.00″);
if (“+”.equals(operator)) {
res =df.format(num11 + num22);
} else if (“-”.equals(operator)) {
res =df.format(num11 – num22);
} else if (“*”.equals(operator)) {
res =df.format(num11 * num22);
} else if (“/”.equals(operator)) {
res =df.format(num11 / num22);
}