Java double reserved number of decimal places

4 methods, all rounded, for example:ImportJava.math.BigDecimal; ImportJava.text.DecimalFormat; ImportJava.text.NumberFormat;  Public classFormat {Doublef = 111231.5585;  Public voidM1 () {BigDecimal bg=NewBigDecimal (f); DoubleF1 = Bg.setscale (2, bigdecimal.round_half_up). Doublevalue ();        System.out.println (F1); }        /*** DecimalFormat conversion is the easiest*/         Public voidm2 () {DecimalFormat DF=NewDecimalFormat ("#.00");        System.out.println (Df.format (f)); }        /*** String.Format Printing is the easiest*/         Public voidm3 () {System.out.println (String.Format ("%.2f", F)); }         Public voidM4 () {NumberFormat NF=numberformat.getnumberinstance (); Nf.setmaximumfractiondigits (2);        System.out.println (Nf.format (f)); }         Public Static voidMain (string[] args) {format F=Newformat ();            F.M1 ();            F.M2 ();            F.M3 ();        F.M4 (); }    }//There is also a direct upward fetching of integersclass= "Title Content-title" >//Java:java function </H2> <div id=content class= "content mod-cs-content text-content clearfix" >//Math.floor (), Math.ceil (), bigdecimal are all rounding functions in Java, but the return values are not the sameMath.floor () The return value calculated by the function is the value after the decimal point such as: Math.floor (3.2) returns 3 Math.floor (3.9) returns 3 Math.floor (3.0) returns a 3 Math.ceil () Ceil function that returns an integer part as long as the decimal point is not 0+1such as: Math.ceil (3.2) returns 4 Math.ceil (3.9) returns 4 Math.ceil (3.0) Return 3 </DIV>

Java double reserved number of decimal places