如下是我写的一段代码:
public class NumberTest {
/**
* @param args
*/
public static void main(String[] args) {
System.out.println(formatDouble(5.225));
System.out.println(formatDouble(5.226));
System.out.println(formatDouble(5.2251));
}
private static String formatDouble(double data)
{
String ret = null;
try {
NumberFormat form = NumberFormat.getInstance();
String mask = "###0.00";
((DecimalFormat)form).applyPattern(mask);
ret = form.format(data);
} catch (Exception e) {
e.printStackTrace();
ret = null;
}
return ret;
}
}
输出结果为:
5.22
5.23
5.23
为什么第一个没有四舍五入呢???