Java Reference
In-Depth Information
JAXB
JAXB is an older Java specification and is not defined by JAX-RS. JAXB is an annotation
framework that maps Java classes to XML and XML schema. It is extremely useful because
instead of interacting with an abstract representation of an XML document, you can work
with real Java objects that are closer to the domain you are modeling. JAX-RS has built-in
support for JAXB, but before we review these handlers, let's get a brief overview of the
JAXB framework.
Intro to JAXB
A whole book could be devoted to explaining the intricacies of JAXB, but I'm only going to
focus here on the very basics of the framework. If you want to map an existing Java class to
XML using JAXB, there are a few simple annotations you can use. Let's look at an example:
@XmlRootElement
(
name
=
"customer"
)
@XmlAccessorType
(
XmlAccessType
.
FIELD
)
public
public class
class
Customer
Customer
{
@XmlAttribute
protected
protected
int
int
id
;
@XmlElement
protected
protected
String fullname
;
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
; }
public
public
String
getFullName
() {
return
return this
this
.
fullname
; }
public
public
void
void
setFullName
(
String name
} {
this
this
.
fullname
=
name
; }
}
The
@javax.xml.bind.annotation.XmlRootElement
annotation is put on Java classes to
denote that they are XML elements. The
name()
attribute of
@XmlRootElement
specifies the
string to use for the name of the XML element. In our example, the annotation
@Xm-
lRootElement
specifies that our
Customer
objects should be marshalled into an XML ele-
ment named
<customer>
.
The
@javax.xml.bind.annotation.XmlAttribute
annotation was placed on the
id
field
of our
Customer
class. This annotation tells JAXB to map the field to an
id
attribute on the
main
<Customer>
element of the XML document. The
@XmlAttribute
annotation also has a
