What's the difference between annotating a class with @XMLRootElement and @XMLType. I've been annotating classes with @XMLType when the structure will be used more than once within an XML schema and with @XMLRootElement when it will be used only once - is this the best approach?
A different but related question which I'll include here. The @XMLType annotation has an propOrder attribute to specify in which order its elements appear - is there an equivalent for @XMLRootElement?
I'm using these annotations in conjunction with JAX-WS annotations to create web services if that makes any difference.
The difference between XmlRootElement and XmlType is a matter of scoping. Remember this annotation is merely dictating the creation of the schema used to generate your XML. The XmlRootElement denotes a global element (with an anonymous or schema type):
<xs:element name=foo type="bar"> </xs:element> <-- schema type
while the XmlType is used to denote a local element (with an anonymous or complex type):
<xs:complexType name=bar> </xs:complexType> <-- complex type
The main differences in local/global here are in the hierarchy of the schema your object will appear in and whether you are declaring a schema type or complex type. The documentation for both of these annotations is well written and includes examples:
EDIT: Addressing the propOrder question: you can use it on a global element if you are also declaring a local type:
@XmlRootElement (name="PersonElement")
@XmlType (propOrder={"firstname", "lastname"})
public class People{
@XmlElement
public String firstname;
public String lastname;
}
This will yield something like:
<xs:element name="PersonElement" type="People"/>
<xs:complexType name="People">
<xs:sequence>
<xs:element name="firstname" type="xs:string"/>
<xs:element name="lastname" type="xs:string"/>
</xs:sequence>
</xs:complexType>