d没传进去,还有类名、包名最好不要用汉字哈
public static void main(String[] args) {
double d = 3.1415926;
String result = String.format("%.2f", d);
System.out.println(result);
}
api用错
public static String format1(double value) {
BigDecimal bd = new BigDecimal(value);
bd = bd.setScale(2, RoundingMode.HALF_UP);
return bd.toString();
}