How to convert nested xml element with attributes to Java Object using JAXB?

hi experts,

i have this xml:-

<?xml version="1.0" encoding="UTF-8"?>
<employee id="ROOT">
    <employee id="employee1">
        <employee id="employee2"/>
        <employee id="employee3"/>
    </employee>
    <employee id="employee4">
        <employee id="employee5"/>
    </employee>
</employee>

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and my java object is:-

public class Employee{
    public String id;
    public List<Employee> empList;

    public Employee(){
        empList = new ArrayList<Employee>();
    }
}

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how do i convert the Nested xml element to the java object define above?

the case based on above, the final result where the java object will hold is

Employee object has id="ROOT" and its empList will have 2 Employee object which id are "employee1" and "employee4" and so on.

I've searched on google, all of the example was meant for simple xml 1 level element which can't apply to my case as the xml has nested elements.

can Jaxb convert it?

please advice
RonjerAsked:
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girionisCommented:
You create elements based on an xsd. If you want to nest elements you need to define this structure in your xsd file. You could do *something* like the following:

<xsd:element name="Employee">
		<xsd:complexType>
			<xsd:sequence>
				<xsd:element minOccurs="1" ref="Employee />
			</xsd:sequence>
		</xsd:complexType>
	</xsd:element>

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RonjerAuthor Commented:
hi there,

i think you misinterpret my question, what i want is to convert the xml given example to java object using JAXB 2. please advice
girionisCommented:
In order to do that you need to have a schema first. Otherwise JAXB does not know how to convert XML to Java classes. First you define the schema and then you convert your XML.

Have a look here for a simple tutorial: http://jaxb.java.net/tutorial/section_1_3-Hello-World.html#Hello%20World
and here for more information: http://jaxb.java.net/tutorial/
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RonjerAuthor Commented:
Is there no way to convert the xml into java object directly instead relying on the schema?
the xml is not generated on my side, its passed from other source. I found out that Jaxb has rich set of Annotations that can annotate fields to unmarshal xml into java object.

my environment is :-
win 7,
jdk 6

please advice
RonjerAuthor Commented:
found the solution,

all that need to do is annotate the java class given below:-

@XmlRootElement(name="country")
@XmlAccessorType(XmlAccessType.FIELD)
class Employee {

    @XmlAttribute
    private String id;

    @XmlElement(name="employee")
    private List<Employee> empList;

}

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with this xml:- "mydata.xml" added country element to identify the root element

<?xml version="1.0" encoding="UTF-8"?>
<country>
<employee id="ROOT">
    <employee id="employee1">
        <employee id="employee2"/>
        <employee id="employee3"/>
    </employee>
    <employee id="employee4">
        <employee id="employee5"/>
    </employee>
</employee>
</country>

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the procedure to convert it is straight forward:-


public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Employee.class);
        
        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("mydata.xml");
        Employee employee = (Employee) unmarshaller.unmarshal(xml);
        
        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(employee, System.out);
    }
}

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the above code however were provided by another expert on JAXB matter:- credit should be given to him "Blaise Doughan"

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RonjerAuthor Commented:
because the question has be idle for some time, and i found the solution provided by yet another expert on this JAXB matter solely, since it gets the job done and simple to execute, therefore i accept it as a solid solution
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