Java: Rounding the double value to five, retaining the two decimal places, double rounding to five

Java: Rounding the double value to five, retaining the two decimal places, double rounding to five
1. Functions

The double value in the program is accurate to the two digits after the decimal point. It can be rounded up or truncated.

For example, if the input value is 12345.6789, the output value can be 12345.68 or 12345.67. You can use the RoundingMode. UP/RoundingMode. DOWN parameter to determine whether to rounding the value ).

2. Implementation Code

Package com. clzhang. sample; import java. math. bigDecimal; import java. math. roundingMode; import java. text. decimalFormat; import java. text. numberFormat; public class DoubleTest {/*** retain two decimal places, rounding an old method * @ param d * @ return */public static double formatDouble1 (double d) {return (double) Math. round (d * 100)/100 ;}
/*** The BigDecimal class provides operations for arithmetic, scale manipulation, rounding, comparison, hashing, and format conversion. * @ param d * @ return */public static double formatDouble2 (double d) {// the old method is no longer recommended. // BigDecimal bg = new BigDecimal (d ). setScale (2, BigDecimal. ROUND_HALF_UP );
// New method. If no rounding is required, you can use RoundingMode. DOWN BigDecimal bg = new BigDecimal (d). setScale (2, RoundingMode. UP );
Return bg. doubleValue ();}/*** NumberFormat is the abstract base class for all number formats. * This class provides the interface for formatting and parsing numbers. * @ param d * @ return */public static String formatDouble3 (double d) {NumberFormat nf = NumberFormat. getNumberInstance ();
// Retain two decimal places nf. setMaximumFractionDigits (2 );
// If no rounding is required, you can use RoundingMode. DOWN nf. setRoundingMode (RoundingMode. UP );
Return nf. format (d );}
/*** This method is quite simple. * DecimalFormat is a concrete subclass of NumberFormat that formats decimal numbers. * @ param d * @ return */public static String formatDouble4 (double d) {DecimalFormat df = new DecimalFormat ("#. 00 ");
Return df. format (d );}
/*** This method is quite convenient if it is only used to format the values in the program and then output them. * It should be used like this: System. out. println (String. format ("%. 2f ", d); * @ param d * @ return */public static String formatDouble5 (double d) {return String. format ("%. 2f ", d);} public static void main (String [] args) {double d = 12345.67890; System. out. println (formatDouble1 (d); System. out. println (formatDouble2 (d); System. out. println (formatDouble3 (d); System. out. println (formatDouble4 (d); System. out. println (formatDouble5 (d ));}}

3. Output

12345.68
12345.68
12,345.68
12345.68
12345.68

In a French Environment, except for the first two methods, the last three methods will display the decimal point as a comma.