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Revision as of 16:19, 19 September 2008

Overview

The following example will demonstrate how to use EclipseLink's JAXB functionality to:

  • Generate JAXB-annotated Java classes from an XML Schema using the JAXB Compiler
  • Unmarshal an XML Document
  • Modify the XML data using the interfaces generated by the compiler
  • Marshal the modified data to XML

Setup

  1. Ensure that you have EclipseLink correctly installed and configured for your environment. Please see EclipseLink/Installing and Configuring EclipseLink for more information.
  2. Ensure that you have ANT correctly installed and configured.
  3. Unzip the Example ZIP file to a new directory.
  4. Edit the env.properties file in the root directory of the example and specify the path to your EclipseLink jlib directory:
...
# Edit eclipselink.jlib to point to your EclipseLink jlib directory
eclipselink.jlib=C:/EclipseLink-1.0/eclipselink/jlib
...

You can compile and run the Example at any time by typing ant from the Example directory.

Running the JAXB Compiler

The JAXB compiler can be run to generate JAXB-annotated Java classes from an XML Schema:

<ECLIPSELINK_HOME>/eclipselink/bin/jaxb-compiler.sh <source-file.xsd> [-options]
<ECLIPSELINK_HOME>\eclipselink\bin\jaxb-compiler.cmd <source-file.xsd> [-options]

Options include:
   -d <dir>                     Specifies the output directory for generated files
   -p <pkg>                     Specifies the target package
   -classpath <arg>             Specifies where to find user class files
   -verbose                     Enable verbose output
   -quiet                       Suppress compiler output
   -version                     Display version information

For a complete list of compiler options:
   jaxb-compiler.sh -help

Example:
   jaxb-compiler.sh -d jaxb-compiler-output config/Customer.xsd 

In this example, the JAXB Compiler is run from the "run.jaxb.compiler" task in the ANT build file.

Creating a JAXBContext using jaxb.properties

The standard way to specify which JAXB implementation should be used is through a file called jaxb.properties, which contains a single property, javax.xml.bind.context.factory. This file must be available on the classpath in the corresponding package (in this example, "org.example.customer_example"). To specify that the EclipseLink JAXB implementation should be used, your jaxb.properties file should have the following content:

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory

In our example, we create the JAXBContext as follows:

JAXBContext jaxbContext = JAXBContext.newInstance("org.example.customer_example");

An alternate way to create a new JAXBContext is to supply an array of Class objects. Again, the jaxb.properties file must be available on the classpath in the corresponding package:

Class[] classes = new Class[4]; 
classes[0] = org.example.customer_example.AddressType.class; 
classes[1] = org.example.customer_example.ContactInfo.class; 
classes[2] = org.example.customer_example.CustomerType.class; 
classes[3] = org.example.customer_example.PhoneNumber.class; 
JAXBContext jaxbContext = JAXBContext.newInstance(classes);

Unmarshalling the XML Document

With a JAXBContext created, we can now unmarshal an XML document using the statically generated classes:

File file = new File("Customer-data.xml");
Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
StreamSource source = new StreamSource(file);
JAXBElement customerElement = unmarshaller.unmarshal(source, CustomerType.class);
CustomerType customer = (CustomerType) customerElement.getValue();

Modify the Objects

Below are examples of manipulating the XML data using the JAXB-generated static classes. Note that there are JavaBean-type accessors on the static interfaces.

Modifying the ShippingAddress ZipCode :

customer.getContactInfo().getShippingAddress().setZipCode("27601");

Adding a new PhoneNumber :

PhoneNumber homePhoneNumber  = new ObjectFactory().createPhoneNumber();
homePhoneNumber.setType("home");
homePhoneNumber.setValue("(613) 555-3333");
customer.getContactInfo().getPhoneNumber().add(homePhoneNumber);

Note the use of the ObjectFactory class to create a new PhoneNumber object. In addition to generating the model classes used in this example, the JAXB compiler also generates an ObjectFactory class that can be used to create any of the generated types.

Removing all "cell" PhoneNumbers :

ArrayList phoneNumbersToRemove = new ArrayList();
List phoneNumbers = customer.getContactInfo().getPhoneNumber();
Iterator it = phoneNumbers.iterator();
while (it.hasNext()) {
    PhoneNumber phoneNumber = (PhoneNumber) it.next();
    if (phoneNumber.getType().equals("cell")) {
        phoneNumbersToRemove.add(phoneNumber);
    }
}
phoneNumbers.removeAll(phoneNumbersToRemove);

Download

org.eclipse.persistence.example.jaxb.zip