Java example of JAXB @XmlRootElement annotation in detail along with its usage during marshalling and unmarshalling operations.
1. @XmlRootElement Annotation
The @XmlRootElement maps a class or an enum type to an XML element. When a top-level class or an enum type is annotated with the @XmlRootElement annotation, then its value is represented as an XML element in an XML document.
2. Syntax
We can use the annotation without providing a specific name. In the following example, the XML tag will be generated as “<Employee>“
@XmlRootElement
public class Employee implements Serializable {
//...
}Or, we can provide a specific name to the generated XML tag. In the following example, the XML tag will be generated as “<employee>“
@XmlRootElement(name = "employee")
public class Employee implements Serializable {
//...
}The @XmlRootElement annotation can be used with the following annotations:
@XmlType@XmlEnum@XmlAccessorType@XmlAccessorOrder
@XmlRootElement(name = "employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class Employee implements Serializable {
//...
}2. JAXB @XmlRootElement Example
Now see a few examples of how using @XmlRootElement changes the XML representations.
2.1. @XmlRootElement with ‘name’ attribute
@XmlRootElement(name = "employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class EmployeeData implements Serializable {
private static final long serialVersionUID = 1L;
private Integer id;
private String firstName;
private String lastName;
}The above converts to:
<employee>
<id>1</id>
<firstName>Lokesh</firstName>
<lastName>Gupta</lastName>
</employee>2.2. @XmlRootElement without ‘name’ attribute
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class EmployeeData implements Serializable {
private static final long serialVersionUID = 1L;
private Integer id;
private String firstName;
private String lastName;
}The above converts to:
<EmployeeData>
<id>1</id>
<firstName>Lokesh</firstName>
<lastName>Gupta</lastName>
</EmployeeData>Drop me your questions in the comments section.
Happy Learning !!
@XmlRootElement(name = “ns0:assetBean”)
@XmlAccessorType(XmlAccessType.FIELD)
it is not allowing to put ‘:’ inside name.
I’m returning a class’s object using @XmlRootElement annotation …. But at runtime it is giving
HTTP Status 500 – Internal Server Error
Type Status Report
Message Internal Server Error
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
while there is no output on console… HELP !!
Please share the stack trace.
If i want a ArrayList in my XML how should we do that ?
How to avoid root element? For example:
I have java classes Application and Person.
class Application { Person person; String arbitraryComment; } class Person { String firstName; String lastName; }I get xml structure like this:
<application> <person> <firstName>?</firstName> <lastName>?</lastName> </person> <arbitraryComment>?</arbitraryComment> </application>And I would want xml structure to be:
<application> <firstName>?</firstName> <lastName>?</lastName> <arbitraryComment>?</arbitraryComment> </application>Here root node is “application”. It is not possible (also not advisable) to avoid “person” node.