Following is a very straightforward and minimal example of how to serialize & deserialize a class in Java.
The class we will serialize & deserialize to and from XML is a Contacts class that has a map of emails & names associated with the emails.
/**
*
*/
import javax.xml.bind.annotation.XmlRootElement;
import java.util.LinkedHashMap;
/**
*
*/
@XmlRootElement (name="contacts")
public class Contacts {
private LinkedHashMap<String, String> map = new LinkedHashMap<String, String>();
public LinkedHashMap<String, String> getMap() {
return map;
}
public void setMap(LinkedHashMap<String, String> map) {
this.map = map;
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}
The class where we will be serializing and deserializing from first creates the contacts so :
Contacts cmap = new Contacts();
cmap.getMap().put("mr.arthur.white@gmail.com", "Arthur White");
cmap.getMap().put("arthur.uthersonn@gmail.com", "Arthur Uthersonn");
Then it seriealizes the maps so:
SerializeToXML sxml = new SerializeToXML();
sxml.serialize(cmap,outputContactsFile);
private void serialize(Contacts map, String xmlFile ) {
try {
JAXBContext jxbCntxt = JAXBContext.newInstance(Contacts.class);
Marshaller marshaller = jxbCntxt.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
// output file to console
marshaller.marshal(map, System.out);
// save to xml file
marshaller.marshal(map, new File(xmlFile));
} catch (Exception e) {
e.printStackTrace();
}
}
And it deserializes it so :
sxml.deSerialize(outputContactsFile);// deserealize the map
private void deSerialize(String xmlFile ) {
try {
JAXBContext jxbCntxt = JAXBContext.newInstance(Contacts.class);
Unmarshaller unmarshaller = jxbCntxt.createUnmarshaller();
Contacts cmap= (Contacts) unmarshaller.unmarshal(new File(xmlFile));
System.out.println("Number of contacts : " + cmap.getMap().size());
} catch (Exception e) {
e.printStackTrace();
}
}
The output of the above is as follows :
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<contacts>
<map>
<entry>
<key>mr.arthur.white@gmail.com</key>
<value>Arthur White</value>
</entry>
<entry>
<key>arthur.uthersonn@gmail.com</key>
<value>Arthur Uthersonn</value>
</entry>
</map>
</contacts>
Number of contacts : 2
And ofcourse the source repository is this.