Annotation Type XmlRootElement



  • @Retention(RUNTIME)
    @Target(TYPE)
    public @interface XmlRootElement
    Maps a class or an enum type to an XML element.

    Usage

    The @XmlRootElement annotation can be used with the following program elements:

    • a top level class
    • an enum type

    See "Package Specification" in javax.xml.bind.package javadoc for additional common information.

    When a top level class or an enum type is annotated with the @XmlRootElement annotation, then its value is represented as XML element in an XML document.

    This annotation can be used with the following annotations: XmlType, XmlEnum, XmlAccessorType, XmlAccessorOrder.

    Example 1: Associate an element with XML Schema type

         // Example: Code fragment
         @XmlRootElement
         class Point {
            int x;
            int y;
            Point(int _x,int _y) {x=_x;y=_y;}
         }
     
         //Example: Code fragment corresponding to XML output
         marshal( new Point(3,5), System.out);
     
    
    
         <!-- Example: XML output -->
         <point>
           <x> 3 </x>
           <y> 5 </y>
         </point>
     
    The annotation causes an global element declaration to be produced in the schema. The global element declaration is associated with the XML schema type to which the class is mapped.
    
    
         <!-- Example: XML schema definition -->
         <xs:element name="point" type="point"/>
         <xs:complexType name="point">
           <xs:sequence>
             <xs:element name="x" type="xs:int"/>
             <xs:element name="y" type="xs:int"/>
           </xs:sequence>
         </xs:complexType>
     

    Example 2: Orthogonality to type inheritance

    An element declaration annotated on a type is not inherited by its derived types. The following example shows this.

         // Example: Code fragment
         @XmlRootElement
         class Point3D extends Point {
             int z;
             Point3D(int _x,int _y,int _z) {super(_x,_y);z=_z;}
         }
    
         //Example: Code fragment corresponding to XML output *
         marshal( new Point3D(3,5,0), System.out );
     
    
         <!-- Example: XML output -->
         <!-- The element name is point3D not point -->
         <point3D>
           <x>3</x>
           <y>5</y>
           <z>0</z>
         </point3D>
    
         <!-- Example: XML schema definition -->
         <xs:element name="point3D" type="point3D"/>
         <xs:complexType name="point3D">
           <xs:complexContent>
             <xs:extension base="point">
               <xs:sequence>
                 <xs:element name="z" type="xs:int"/>
               </xs:sequence>
             </xs:extension>
           </xs:complexContent>
         </xs:complexType>
     
    Example 3: Associate a global element with XML Schema type to which the class is mapped.
         //Example: Code fragment
         @XmlRootElement(name="PriceElement")
         public class USPrice {
             @XmlElement
             public java.math.BigDecimal price;
         }
     
    
         <!-- Example: XML schema definition -->
         <xs:element name="PriceElement" type="USPrice"/>
         <xs:complexType name="USPrice">
           <xs:sequence>
             <xs:element name="price" type="xs:decimal"/>
           </sequence>
         </xs:complexType>
     
    Since:
    1.6, JAXB 2.0
    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element Description
      String name
      local name of the XML element.
      String namespace
      namespace name of the XML element.
    • Element Detail

      • namespace

        String namespace
        namespace name of the XML element.

        If the value is "##default", then the XML namespace name is derived from the package of the class ( XmlSchema ). If the package is unnamed, then the XML namespace is the default empty namespace.

        Default:
        "##default"
      • name

        String name
        local name of the XML element.

        If the value is "##default", then the name is derived from the class name.

        Default:
        "##default"