Java retains two decimal places (rounded)

Import Java.math.bigdecimal;import Java.text.decimalformat;import Java.text.numberformat;public class TestNumber { public static Double num = 3.1015926;public static Double zero = 0.00000;//method One: printing is easiest, always at the end there is a two-bit decimal public static void function 1 () {System.out.println (String.Format ("%.2f", num)); System.out.println (String.Format ("%.2f", Zero));} Method Two: After conversion is a string type public static void Function2 () {DecimalFormat df = new DecimalFormat ("0.00"); SYSTEM.OUT.PRINTLN (Df.format (num)); System.out.println (Df.format (zero));} Method Three: After conversion is a double type, but will omit the last 0, only one bit of 0public static void Function3 () {BigDecimal bg1 = new BigDecimal (num);d ouble finalnum = Bg1.setscale (2, bigdecimal.round_half_up). Doublevalue (); System.out.println (Finalnum); BigDecimal bg2 = new BigDecimal (zero);d ouble Finalzero = Bg2.setscale (2, bigdecimal.round_half_up). Doublevalue (); System.out.println (Finalzero);} Method Four: The end of 0 will omit 3.1001->3.1,0.0000->0public static void Function4 () {NumberFormat NF = Numberformat.getnumberinstance (); Nf.setmaximumfractiondIgits (2); SYSTEM.OUT.PRINTLN (Nf.format (num)); System.out.println (Nf.format (zero));} public static void Main (String args[]) {System.out.println ("function1:"); function1 (); System.out.println ("function2:"); function2 (); System.out.println ("Function3:"); Function3 (); System.out.println ("Function4:"); Function4 ();}}

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Java retains two decimal places (rounded)