Java Reference
In-Depth Information
@XmlAttribute
protected
protected
int
int
id
;
@XmlElement
protected
protected
String name
;
@XmlElement
protected
Address address
;
public
public
Customer
() {}
public
public
int
int
getId
() {
return
return this
this
.
id
; }
public
public
void
void
setId
(
int
int
id
) {
this
this
.
id
=
id
; }
...
}
If we were to output an instance of our new
Customer
class that had an
id
of 42, a
name
of
“Bill Burke,” a
street
of “200 Marlborough Street,” a
city
of “Boston,” a
state
of “MA,”
and a
zip
of “02115,” the outputted XML would look like this:
<customer
<customer id=
"42"
>
<name>
<name>
Bill Burke
</name>
</name>
<address>
<address>
<street>
<street>
200 Marlborough Street
</street>
</street>
<city>
<city>
Boston
</city>
</city>
<state>
<state>
MA
</state>
</state>
<zip>
<zip>
02115
</zip>
</zip>
</address>
</customer>
</address>
</customer>
There are a number of other annotations and settings that allow you to do some more com-
plex Java-to-XML mappings. JAXB implementations are also required to have command-
line tools that can automatically generate JAXB-annotated Java classes from XML schema
documents. If you need to integrate with an existing XML schema, these autogeneration
tools are the way to go.
To marshal Java classes to and from XML, you need to interact with the
javax.xml.bind.JAXBContext
class.
JAXBContext
instances introspect your classes to un-
derstand the structure of your annotated classes. They are used as factories for the
javax.xml.bind.Marshaller
and
javax.xml.bind.Unmarshaller
interfaces.
Mar-
shaller
instances are used to take Java objects and output them as XML.
Unmarshaller
in-
stances are used to take XML input and create Java objects out of it. Here's an example of
using JAXB to write an instance of the
Customer
class we defined earlier into XML and then
to take that XML and re-create the
Customer
object:
