almost 9 years ago
Hello Programmers,
A number of times, we need to cast our Java object into an XML or vice-versa. The turms are technically know as marshalling and un-marshalling. There are many different Java libraries to do the same in which Castor and JAXB are commonly used.
I am going to use JAXB as this comes with our JDK 1.6+ package.
Let understand with an example. Suppose we have a company with a number of its employees. So, we all might have similar class hierarchy in our mind to represent it.
package com.evontech.blog;import javax.xml.bind.annotation.XmlElement;import javax.xml.bind.annotation.XmlRootElement;@XmlRootElementpublic class Company {private EmployeeList employeeList;public EmployeeList getEmployeeList() {return employeeList;}@XmlElementpublic void setEmployeeList(EmployeeList employeeList) {this.employeeList = employeeList;}}
package com.evontech.blog;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement
public class Company {
private EmployeeList employeeList;
public EmployeeList getEmployeeList() {
return employeeList;
}
@XmlElement
public void setEmployeeList(EmployeeList employeeList) {
this.employeeList = employeeList;
}
}
In the code snippet above, Annotation @XmlRootElement describe as this class will be the root of the XML. @XmlElement is an element for that root.
That's it. Let's test it.
package com.evontech.blog;import java.io.File;import java.util.ArrayList;import java.util.List;import javax.xml.bind.JAXBContext;import javax.xml.bind.Marshaller;import org.junit.Test;public class BlogTest {@Testpublic void testJaxb() {List<Employee> empoyees = new ArrayList<Employee>();Employee emp1 = new Employee();emp1.setId(1);emp1.setName("Dinesh");empoyees.add(emp1);Employee em2 = new Employee();em2.setId(2);em2.setName("Babita");empoyees.add(em2);EmployeeList empList = new EmployeeList();empList.setEmployees(empoyees);Company company = new Company();company.setEmployeeList(empList);try {File file = new File("D:\\file.xml");if(!file.exists()) {file.createNewFile();}JAXBContext jaxbContext = JAXBContext.newInstance(Company.class);Marshaller jaxbMarshaller = jaxbContext.createMarshaller();// output pretty printedjaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);jaxbMarshaller.marshal(company,file);} catch(Exception e) {e.printStackTrace();}}}
package com.evontech.blog;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import org.junit.Test;
public class BlogTest {
@Test
public void testJaxb() {
List<Employee> empoyees = new ArrayList<Employee>();
Employee emp1 = new Employee();
emp1.setId(1);
emp1.setName("Dinesh");
empoyees.add(emp1);
Employee em2 = new Employee();
em2.setId(2);
em2.setName("Babita");
empoyees.add(em2);
EmployeeList empList = new EmployeeList();
empList.setEmployees(empoyees);
Company company = new Company();
company.setEmployeeList(empList);
try {
File file = new File("D:\\file.xml");
if(!file.exists()) {
file.createNewFile();
}
JAXBContext jaxbContext = JAXBContext.newInstance(Company.class);
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
// output pretty printed
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
jaxbMarshaller.marshal(company,file);
} catch(Exception e) {
e.printStackTrace();
}
}
}
Just run this test case. If you will check the file in your D drive.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?><company><employeeList><employees><id>1</id><name>Dinesh</name></employees><employees><id>2</id><name>Babita</name></employees></employeeList></company>
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<company>
<employeeList>
<employees>
<id>1</id>
<name>Dinesh</name>
</employees>
<employees>
<id>2</id>
<name>Babita</name>
</employees>
</employeeList>
</company>Thanks :)
Happy programming.
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