Jaxb Xml到java.awt

Question

I'm using JAXB for XML biding in my Project, I'm still a beginner. Now i try to bind this XML File to the Class FontStyle

The Xml File looks like this

example.xml

<fontStyle>
  <font>
    <family>Arial</family>
    <style>0</style>
    <size>12</size>
  </font>
  <fontColor>
    <red>0</red>
    <green>0</green>
    <blue>0</blue>
  </fontColor>
  <backgroundColor>
    <red>255</red>
    <green>255</green>
    <blue>255</blue>
  </backgroundColor>
</fontStyle>

This is my FontStyle Class:

FontStyle.java

import java.awt.Color;
import java.awt.Font;


public class FontStyle {

    private Font font;

    private Color fontColor = Color.BLACK;

    private Color backgroundColor = Color.WHITE;

    public FontStyle() {

    }

    public FontStyle(Font font, Color fontColor, Color backgroundColor) {
        this.font = font;
        this.fontColor = fontColor;
        this.backgroundColor = backgroundColor;
    }

    public Font getFont() {
        return font;
    }


    public void setFont(Font font) {
        this.font = font;
    }

    public Color getFontColor() {
        return fontColor;
    }


    public void setFontColor(Color fontColor) {
        this.fontColor = fontColor;
    }


    public Color getBackgroundColor() {
        return backgroundColor;
    }


    public void setBackgroundColor(Color backgroundColor) {
        this.backgroundColor = backgroundColor;
    }


}

I hope anyone can give me an advise how to handle this.

cheers

Answer 1

Types that do not map naturally to a XML representation require writing an XmlAdapter implementation, Font and Color are such types. The code below presents an example of how you can write adapters in your case.

I placed the adapter classes as nested classes in FontStyle class but you can create them as external classes if you wish.

import javax.xml.bind.annotation.*;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
import java.awt.*;

@XmlRootElement
@XmlType(propOrder = {"font", "fontColor", "backgroundColor"}) // to keep ordering consistent with "example.xml"
public class FontStyle {

    private Font font;

    private Color fontColor = Color.BLACK;

    private Color backgroundColor = Color.WHITE;

    public FontStyle() {
    }

    public FontStyle(Font font, Color fontColor, Color backgroundColor) {
        this.font = font;
        this.fontColor = fontColor;
        this.backgroundColor = backgroundColor;
    }

    @XmlJavaTypeAdapter(FontAdapter.class)
    public Font getFont() {
        return font;
    }

    @XmlJavaTypeAdapter(ColorAdapter.class)
    public Color getFontColor() {
        return fontColor;
    }

    @XmlJavaTypeAdapter(ColorAdapter.class)
    public Color getBackgroundColor() {
        return backgroundColor;
    }

    public void setFont(Font font) {
        this.font = font;
    }

    public void setFontColor(Color fontColor) {
        this.fontColor = fontColor;
    }

    public void setBackgroundColor(Color backgroundColor) {
        this.backgroundColor = backgroundColor;
    }

    private static class ColorAdapter extends XmlAdapter<ColorAdapter.ColorValueType, Color> {

        @Override
        public Color unmarshal(ColorValueType v) throws Exception {
            return new Color(v.red, v.green, v.blue);
        }

        @Override
        public ColorValueType marshal(Color v) throws Exception {
            return new ColorValueType(v.getRed(), v.getRed(), v.getBlue());
        }

        @XmlAccessorType(XmlAccessType.FIELD)
        public static class ColorValueType {
            private int red;
            private int green;
            private int blue;

            public ColorValueType() {
            }

            public ColorValueType(int red, int green, int blue) {
                this.red = red;
                this.green = green;
                this.blue = blue;
            }
        }
    }

    private static class FontAdapter extends XmlAdapter<FontAdapter.FontValueType, Font> {

        @Override
        public Font unmarshal(FontValueType v) throws Exception {
            return new Font(v.family, v.style, v.size);
        }

        @Override
        public FontValueType marshal(Font v) throws Exception {
            return new FontValueType(v.getFamily(), v.getStyle(), v.getSize());
        }

        @XmlAccessorType(XmlAccessType.FIELD)
        public static class FontValueType {
            private String family;
            private int style;
            private int size;

            public FontValueType() {
            }

            public FontValueType(String family, int style, int size) {
                this.family = family;
                this.style = style;
                this.size = size;
            }
        }
    }
}

The code to unmarshall example.xml and test the result can look like this:

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import java.io.File;

public class App {
    public static void main(String[] args) throws JAXBException {
        JAXBContext jaxbContext = JAXBContext.newInstance(FontStyle.class);

        // unmarshall "example.xml"
        File exampleFile = new File("example.xml");
        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
        FontStyle fontStyle = (FontStyle) jaxbUnmarshaller.unmarshal(exampleFile);

        // marshall back to XML and print the result
        Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
        jaxbMarshaller.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE); // removes xml declaration line for consistency with "example.xml" file
        jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        jaxbMarshaller.marshal(fontStyle, System.out);
    }
}

Answer 2

Marcin's answer works perfectly but please be aware of the following line of code:

@Override
public ColorValueType marshal(Color v) throws Exception {
    return new ColorValueType(v.getRed(), v.getRed(), v.getBlue());
}

If you try to edit the green in the XML it will cause it to be overwritten with the red value since it's calling the v.getRed() twice.

This would be the correct code.

@Override
public ColorValueType marshal(Color v) throws Exception {
    return new ColorValueType(v.getRed(), v.getGreen(), v.getBlue()); // Changed to getGreen().
}