Generate Spring bean definition from a Java object

Question

Let's suggest that I have a bean defined in Spring:

<bean id="neatBean" class="com..." abstract="true">...</bean>

Then we have many clients, each of which have slightly different configuration for their 'neatBean'. The old way we would do it was to have a new file for each client (e.g., clientX_NeatFeature.xml) that contained a bunch of beans for this client (these are hand-edited and part of the code base):

<bean id="clientXNeatBean" parent="neatBean">
    <property id="whatever" value="something"/>
</bean>

Now, I want to have a UI where we can edit and redefine a client's neatBean on the fly.

My question is: given a neatBean, and a UI that can 'override' properties of this bean, what would be a straightforward way to serialize this to an XML file as we do [manually] today?

For example, if the user set property whatever to be "17" for client Y, I'd want to generate:

<bean id="clientYNeatBean" parent="neatBean">
    <property id="whatever" value="17"/>
</bean>

Note that moving this configuration to a different format (e.g., database, other-schema'd-xml) is an option, but not really an answer to the question at hand.

Answer 1

You can download the Spring-beans 2.5 xsd from here and run xjc on it to generate the Java classes with JAXB bindings. Then you can create the Spring-beans object hierarchy on runtime (and manipulate it as you wish) and then serialize it to an XML string using the JAXB Marshaller as shown in Pablojim's answer.

Answer 2

I'd use Jax-b to do this. You'de create a bean object with a list of property objects inside.

@XmlRootElement(name = "bean")
@XmlAccessorType(XmlAccessType.FIELD)

public class Bean {

  @XmlAttribute
  private String id;
  @XmlAttribute
  private String parent;

  @XmlElement(name="property")
  private List<BeanProperty> properties

Then You'd need to also add annotations to BeanProperty. Then when you have a populated object simply marshal it to xml using jaxb:

Marshaller m = jc.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
m.marshal( myBean, System.out );

For full code examples see: http://java.sun.com/webservices/docs/2.0/tutorial/doc/JAXBUsing.html

Alternatively you could use Groovy - you can drop it in place and creating this xml would be very simple... : http://www.ibm.com/developerworks/java/library/j-pg05199/index.html