Floating-point format in java

You can do this with a combination of DecimalFormat and < a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Double.html#parseDouble(java.lang.String)"> Double.parseDouble () . I created a custom Double called FormattedDouble that extends DecimalFloat to accomplish what you want. See the class code:

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;

public class FormattedDouble extends DecimalFormat {

    private static final long serialVersionUID = 1L;
    private DecimalFormatSymbols symbols;
    private String stringValue;
    private double value;

    public FormattedDouble(double value) {
        super("#.##"); // Customize the format here.
        symbols = new DecimalFormatSymbols();
        symbols.setDecimalSeparator('.');
        symbols.setGroupingSeparator(' ');
        setDecimalFormatSymbols(symbols);
        this.setStringValue(format(value));
        this.setValue(Double.parseDouble(this.getStringValue()));
    }

    public double getValue() {
        return value;
    }

    public void setValue(double value) {
        this.value = value;
    }

    public String getStringValue() {
        return stringValue;
    }

    public void setStringValue(String stringValue) {
        this.stringValue = stringValue;
    }

}

This, getting a Double with the number of houses limited (Using the example you gave), is simple:

public class Main {

    public static void main(String[] args) {
        double example = new FormattedDouble(3.1412233).getValue(); // Returns 3.14.
        System.out.println(example); // Outputs 3.14.
    }

}

You can adapt the FormattedDouble class to allow changes in the number of houses. Read the DecimalFormat documentation to be able to adapt to your needs.

EDIT:

It's not exactly what you want because it's not possible. A Double is a Double, and period (If you want to change the format , need format ). It is possible to simulate what you want, change at the "reading time", creating a custom Double as I did.