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 !!
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