Java double retains the 0 decimal point problem, java reserved decimal point problem

1. Format with DecimalFormat,
DecimalFormat df=new DecimalFormat ("0.00");

System.out.println (Df.format (1.2));

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What if I have to use a double type?

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2.

double-type variable in Java preserves two decimal points

Mport java.text.*;

DecimalFormat df=new DecimalFormat (". # #");
Double d=1252.2563;
String St=df.format (d);
System.out.println (ST);

JAVA four ways to keep two decimal places

importjava.math.BigDecimal;

import java.text.DecimalFormat; import java.text.NumberFormat; public class format {      double f =  111231.5585 ;      public void m1() {          BigDecimal bg =  new BigDecimal(f);          double f1 = bg.setScale( 2 , BigDecimal.ROUND_HALF_UP).doubleValue();          System.out.println(f1);      }      /**       * DecimalFormat转换最简便       */      public void m2() {          DecimalFormat df =  new DecimalFormat( "#.00" );          System.out.println(df.format(f));      }      /**       * String.format打印最简便       */      public void m3() {          System.out.println(String.format( "%.2f" , f));      }      public void m4() {          NumberFormat nf = NumberFormat.getNumberInstance();          nf.setMaximumFractionDigits( 2 );          System.out.println(nf.format(f));      }      public static void main(String[] args) {          format f =  new format();          f.m1();          f.m2();          f.m3();          f.m4();      } } How does Java implement to keep a small number only after two bits.

Import Java.text.NumberFormat;
public class Testnumberformat {
public static void Main (string[] args) {
NumberFormat NF = numberformat.getinstance ();
Nf.setmaximumfractiondigits (2);
Double var = 8.88888;
System.out.println (Nf.format (Var));
}
}

Java double retains the 0 decimal point problem, java reserved decimal point problem