Contact Application on Spring by Example

I've just updated Spring by Example to have a multi-module Contact Application. It's meant to be an example of an architecture pattern to follow for larger applications.

The DAO module has the DB schema, JPA entities, and uses Spring Data JPA repositories. It also has a Spring Profile for HSQL DB and PostgreSQL. The tests and webapp default to using the in memory database and PostgreSQL is meant to be used in the production deployment of the webapp.

The WS Beans module are JAXB beans generated from XSDs. They are generated to have a fluent API (ex: new Person.withId(1).withFirstName("John")) and are meant to provide an easy way to create different models for external APIs that can be easily serialized to JSON & XML.

The Services module uses the WS Beans (JAXB Beans) for it's main model and for any APIs. It is meant to be the layer where all business logic is located. It converts to and from the JPA entities & WS Beans using Dozer. It configures Spring's transactional support and Spring Security.

REST Services exposes the Services layer and provides clients & controllers for all REST APIs. All APIs can be exposed over JSON & XML. It has the standard JSON media type and a custom one that also includes class information for more complex data models.

The contact webapp has a standard JSP UI, Sencha ExtJS, and also a Sencha Touch UI.

There is a shared test module to keep inter-module dependencies less complex. The DAO, Services, and REST Services layer each have an abstract test base that creates a shared test context. The DAO and Services both create an in memory DB, and use Spring's transactional test framework to rollback transactions after each test runs. The REST Services module creates an in memory DB and an embedded Jetty instance. The embedded Jetty has it's own Spring context, separate from the test one. The embedded Jetty context loads as much as possible of the production Spring configuration, and the test context just loads the REST clients. You may also want to look at Spring Test MVC for testing controller, but the Contact Application approach runs very quickly and is really a full integration test.

• Contact Application DAO
• Contact Application Web Service Beans
• Contact Application Services
• Contact Application REST Services
• Contact Application Webapp
• Contact Application Test

Spring Data JPA Examples on Spring by Example

I've just updated Spring by Example to have two Spring Data JPA examples. One has basic repository use and shows how to make some custom queries, and the other one shows how to use Spring Data JPA auditing. All of the main webapps using JPA were updated to use Spring Data JPA and all JPA examples were updated to use Hibernate 4.1. I ran into issues updating the Hibernate template examples, so they will stay on Hibernate 3.6.

There were other miscellaneous updates. The AJAX tiles work in the web flow examples wasn't working so I removed it for now.

I'll be continuing to work on REST and UI examples, using ExtJS and Sencha Touch.

• Spring Data JPA
  


• Spring Data JPA Auditing
  

SpringOne & Spring By Example Update

I've just updated Spring by Example to Spring 3.1 and Java 6. The new Spring by Example Repository is on GitHub.

Here are some general comments about the latest release. The Maven group and artifact IDs have been changed back to standard Maven naming and also all project dependencies (no OSGi ones in standard examples). The project is now one large multi-module project structure to make it easier to maintain and upgrade releases. Originally the goal was to have standalone projects so it was easier for someone to get started, but I don't have time to maintain the project this way anymore.

The GWT examples have been removed from the documentation and are not in git. If I have time in the future I may add them back, but I'll be focusing on some standard JS UI examples. The Spring dm Server (OSGi) examples have not been updated, but are still available in the documentation. They still located in Subversion since I won't actively try to maintain them anymore. Spring by Example JDBC has been removed and all projects (except for OSGi ones) have been changed to use the Spring JDBC Custom Namespace. Between the this namespace and Spring Data JPA, nothing is really necessary in this module. I'll be starting on a Spring Data JPA example next week.

Spring JAXB with CDATA Elements

I wanted to configure the Jaxb2Marshaller to support CDATA elements. This example works with Spring 3.1 and Java 6, using the Java 6 restricted XML parser classes to configure the CDATA elements.



<bean id="marshaller" class="org.springbyexample.marshaller.CdataJaxb2Marshaller">
     <property name="cdataElements">
         <list>
             <value>^value</value>
         </list>
     </property>
...


import java.io.IOException;
import java.io.OutputStream;

import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.transform.Result;
import javax.xml.transform.stream.StreamResult;

import org.apache.commons.lang.ArrayUtils;
import org.springframework.oxm.MarshallingFailureException;
import org.springframework.oxm.XmlMappingException;
import org.springframework.oxm.jaxb.Jaxb2Marshaller;
import org.springframework.oxm.mime.MimeContainer;


public class CdataJaxb2Marshaller extends Jaxb2Marshaller {
    
    private String[] cdataElements;
    
    public String[] getCdataElements() {
        return cdataElements;
    }

    public void setCdataElements(String[] cdataElements) {
        this.cdataElements = cdataElements;
    }
    
    @Override
    public void marshal(Object graph, Result result, MimeContainer mimeContainer) throws XmlMappingException {
        if (ArrayUtils.isNotEmpty(cdataElements)) {
            try {
                Marshaller marshaller = createMarshaller();
    
                com.sun.org.apache.xml.internal.serialize.XMLSerializer serializer =
                        createXMLSerializer(cdataElements, ((StreamResult)result).getOutputStream());
                marshaller.marshal(graph, serializer.asContentHandler());
            } catch (IOException e) {
                throw new MarshallingFailureException(e.getMessage(), e);
            } catch (JAXBException ex) {
                throw convertJaxbException(ex);
            }
        } else {
            super.marshal(graph, result);
        }
    }

    @SuppressWarnings("restriction")
    private com.sun.org.apache.xml.internal.serialize.XMLSerializer createXMLSerializer(String[] cDataElements, OutputStream cOut) {
        // This code is from a sample online: http://jaxb.java.net/faq/JaxbCDATASample.java
        // configure an OutputFormat to handle CDATA
        com.sun.org.apache.xml.internal.serialize.OutputFormat of = new com.sun.org.apache.xml.internal.serialize.OutputFormat();

        // specify which of your elements you want to be handled as CDATA.
        // The use of the '^' between the namespaceURI and the localname
        // seems to be an implementation detail of the xerces code.
        // When processing xml that doesn't use namespaces, simply omit the
        // namespace prefix as shown in the third CDataElement below.
        of.setCDataElements(cDataElements); //

        // set any other options you'd like
        of.setPreserveSpace(true);
        of.setIndenting(true);
        of.setPreserveSpace(false);

        // create the serializer
        com.sun.org.apache.xml.internal.serialize.XMLSerializer serializer = new com.sun.org.apache.xml.internal.serialize.XMLSerializer(of);
        serializer.setOutputByteStream(cOut);

        return serializer;
    }

}