The Java Developers Almanac 1.4


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Home > List of Packages > java.beans  [12 examples] > Serialization  [4 examples]

e7. Serializing a Bean to XML

The XMLEncoder class serializes an object in similar fashion to java.io.ObjectOutput. However, unlike ObjectOutput, which persists all non-transient private and public data, the XMLEncoder only persists the value of public properties. In particular, for every public property, XMLEncoder calls its getter method and persists the returned value. In deserialization, a newly created object is initialized with these persisted property values. Therefore, any private state that is not associated with a property will, by default, not be persisted.

See also e8 Deserializing a Bean from XML.

    // Create an object and set properties
    MyClass o = new MyClass();
    o.setProp(1);
    o.setProps(new int[]{1, 2, 3});
    
    try {
        // Serialize object into XML
        XMLEncoder encoder = new XMLEncoder(new BufferedOutputStream(
            new FileOutputStream("outfilename.xml")));
        encoder.writeObject(o);
        encoder.close();
    } catch (FileNotFoundException e) {
    }
    // This class defines two properties - prop and props
    public class MyClass {
        // The prop property
        int i;
        public int getProp() {
            return i;
        }
        public void setProp(int i) {
            this.i = i;
        }
    
        // The props property
        int[] iarray = new int[0];
        public int[] getProps() {
            return iarray;
        }
        public void setProps(int[] iarray) {
            this.iarray = iarray;
        }
    }
Here is the XML data:
    <?xml version="1.0" encoding="UTF-8"?>
    <java version="1.4.0" class="java.beans.XMLDecoder">
        <object class="MyClass">
            <void property="prop">
                <int>1</int>
            </void>
            <void property="props">
                <array class="int" length="3">
                    <void index="0">
                        <int>1</int>
                    </void>
                    <void index="1">
                        <int>2</int>
                    </void>
                    <void index="2">
                        <int>3</int>
                    </void>
                </array>
            </void>
        </object>
    </java>

 Related Examples
e8. Deserializing a Bean from XML
e9. Preventing a Bean Property from Being Serialized to XML
e10. Serializing an Immutable Bean Property to XML

See also: Events   


© 2002 Addison-Wesley.