Java example to write Java object to XML. Information stored in Java objects fields can written into XML file or simply XML string as well.
1) Convert Java Object to XML String
To write Java object to XML String
, first get the JAXBContext
. It is entry point to the JAXB API and provides methods to unmarshal, marshal and validate operations.
Now get the Marshaller
instance from JAXBContext
. It’s marshal()
method marshals Java object into XML. Now this XML can be written to different outputs e.g. string, file or stream.
package com.howtodoinjava.demo; import java.io.File; import java.io.StringWriter; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Marshaller; public class JaxbExample { public static void main(String[] args) { //Java object. We will convert it to XML. Employee employee = new Employee(1, "Lokesh", "Gupta", new Department(101, "IT")); //Method which uses JAXB to convert object to XML jaxbObjectToXML(employee); } private static void jaxbObjectToXML(Employee employee) { try { //Create JAXB Context JAXBContext jaxbContext = JAXBContext.newInstance(Employee.class); //Create Marshaller Marshaller jaxbMarshaller = jaxbContext.createMarshaller(); //Required formatting?? jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE); //Print XML String to Console StringWriter sw = new StringWriter(); //Write XML to StringWriter jaxbMarshaller.marshal(employee, sw); //Verify XML Content String xmlContent = sw.toString(); System.out.println( xmlContent ); } catch (JAXBException e) { e.printStackTrace(); } } }
Program Output.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <employee> <department> <id>101</id> <name>IT</name> </department> <firstName>Lokesh</firstName> <id>1</id> <lastName>Gupta</lastName> </employee>
2) Convert Java Object to XML File
Writing XML to file is very similar to above example. You only need to provide XML file location where you want to write the file.
package com.howtodoinjava.demo; import java.io.File; import java.io.StringWriter; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Marshaller; public class JaxbExample { public static void main(String[] args) { //Java object. We will convert it to XML. Employee employee = new Employee(1, "Lokesh", "Gupta", new Department(101, "IT")); //Method which uses JAXB to convert object to XML jaxbObjectToXML(employee); } private static void jaxbObjectToXML(Employee employee) { try { //Create JAXB Context JAXBContext jaxbContext = JAXBContext.newInstance(Employee.class); //Create Marshaller Marshaller jaxbMarshaller = jaxbContext.createMarshaller(); //Required formatting?? jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE); //Store XML to File File file = new File("employee.xml"); //Writes XML file to file-system jaxbMarshaller.marshal(employee, file); } catch (JAXBException e) { e.printStackTrace(); } } }
Program Output.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <employee> <department> <id>101</id> <name>IT</name> </department> <firstName>Lokesh</firstName> <id>1</id> <lastName>Gupta</lastName> </employee>
3) Read XML Example
If you want to read the XML from file to Java object again, then use this method.
String fileName = "employee.xml"; //Call method which read the XML file above jaxbXmlFileToObject(fileName); private static void jaxbXmlFileToObject(String fileName) { File xmlFile = new File(fileName); JAXBContext jaxbContext; try { jaxbContext = JAXBContext.newInstance(Employee.class); Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller(); Employee employee = (Employee) jaxbUnmarshaller.unmarshal(xmlFile); System.out.println(employee); } catch (JAXBException e) { e.printStackTrace(); } }
Program Output.
Employee [id=1, firstName=Lokesh, lastName=Gupta, department=Department [id=101, name=IT]]
Drop me your questions in comments section.
Happy Learning !!
We have output of one XML file in one object using JAXB.
We want to export the same java object to another XML format with different XML tags.
Basically we want to map one XML to another XML file.
How can we do this ?
Is there any other way to this other that JAXB
thanks, easy to find and implement. A reference for when it’s needed.
Excellent work Lokesh!!
I had a question,
Say I have schema(xsd) and i converted that into pojos’ using xjc.
Now I am converting those into xml.
question here is if certain elements have minOccurs=0 in schema
how they are handled in generating xml using the pojos?
if the data is not there and when i add/set those classes I get empty xml tags.
How can I avoid getting empty xml tags?
Thanks for your help in advance
hello… I was trying to use arraylist for mashalling and unmarshalling.. the marshalling process went smoothly however the unmarshalling printed weird output.. its like this (studentxmltodatabase.Students@3b9a45b3) can you please help me with this?
thank you in advance
You have to include toString() method in your Student class
how to convert text to java object then java object to xml.