Java Reference
In-Depth Information
@XmlAccessorType
(
XmlAccessType
.
FIELD
)
@XmlRootElement
(
name
=
"config"
)
We could write the XML schema by hand, using
vi
or
notepad
, but regular readers such as
yourself undoubtedly expect that I will refuse to do so whenever possible. Instead, I'll use a
JAXB-provided utility,
schemagen
, to generate the XML:
$ schemagen -cp $js/target -d /tmp Configuration.java
This generates a schema file with the hardcoded filename
schema1.xsd
(
.xsd
is the normal fi-
lename extension for XML Schema Definition):
<xs:schema
<xs:schema version=
"1.0"
xmlns:xs=
"http://www.w3.org/2001/XMLSchema"
>
<xs:element
<xs:element name=
"config"
type=
"configuration"
//>
<xs:complexType
<xs:complexType name=
"configuration"
>
<xs:sequence>
<xs:sequence>
<xs:element
<xs:element name=
"screenName"
type=
"xs:string"
minOccurs=
"0"
//>
<xs:element
<xs:element name=
"webProxy"
type=
"xs:string"
minOccurs=
"0"
//>
<xs:element
<xs:element name=
"verbose"
type=
"xs:boolean"
//>
<xs:element
<xs:element name=
"colorName"
type=
"xs:string"
minOccurs=
"0"
//>
</xs:sequence>
</xs:sequence>
</xs:complexType>
</xs:complexType>
</xs:schema>
</xs:schema>
The online source has a commented-up version of this file, renamed to
xml.jaxb.xsd
.
Now we are ready to serialize or deserialize objects.
Example 20-2
shows writing a
Config-
uration
object out to an XML file and then, some time later in the same program (maybe a
subsequent invocation of the program) reading it back in. This code is written as a JUnit test
(see
Avoiding the Need for Debuggers with Unit Testing
) to make it easy to prove that it ac-
tually saves the fields and rereads them.
Example 20-2. JAXB Demonstration Main
// We set up JAXB: the context arg is the package name!
JAXBContext jc
=
JAXBContext
.
newInstance
(
"xml.jaxb"
);
Marshaller saver
=
jc
.
createMarshaller
();
final
final
File f
=
new
new
File
(
"config.save"
);
