DecimalFormat decimalFormat = new DecimalFormat();
decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
decimalFormat.applyPattern(".00");
System.out.print(decimalFormat.format(63.275));
// output : 63.27
System.out.print(decimalFormat.format(64.275));
// output : 64.28
Why are they different?
The value of 63.275 is recorded in computer as 63.27499999999999857891452847979962825775146484375 . As per the Java API doc "https://docs.oracle.com/javase/8/docs/api/java/math/RoundingMode.html#HALF_UP " Behaves as for RoundingMode.UP if the discarded fraction is ≥ 0.5; otherwise, behaves as for RoundingMode.DOWN. so ,
63.27499999999999857891452847979962825775146484375 ~ 63.27
64.275000000000005684341886080801486968994140625 ~ 64.28
public static double roundByPlace(double number, int scale){
BigDecimal bigDecimal = BigDecimal.valueOf(number);
String pattern = "0.";
for(int i = 0; i<scale; i++){
pattern = pattern+"0";
}
DecimalFormat decimalFormat = new DecimalFormat(pattern);
decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
double result = Double.parseDouble(decimalFormat.format(bigDecimal));
return result;
}