Friday, January 22, 2010

Unit Testing Restful Web Services using Restlet and Jaxb

One way to post data to a Restful web services is to Serialize your object using Jaxb (Java Architecture for XML Binding) when you are using Java.  Since you are dealing with Web Services you client code could also be in .Net, javascript, PHP, Rails, etc.  But, in this post we are assuming your client is Java based.  If you Object class is in a separate project from your Test project, one thing that will cause you to pull your hair out is you will get : JAXBException stating errors creating marshaller or unmarshaller, unless you place a jaxb.index file with your Object class in the same package. For example, if the Object that you are Serializing is Sample.java with the package com.acme.businessobjects, then you have to place a jaxb.index file with the package com.acme.businessobjects. Within the jaxb.index file just place one line with just the class name: Sample, and that's it.
Here is link to javadoc that discuss this: http://java.sun.com/javase/6/docs/api/javax/xml/bind/JAXBContext.html
The best way to understand Jaxb is to create a sample object called Sample, and create a test case
To demonstrate this issue create 2 projects , one that contains the Sample.java class, and one the contains you Test case. Note: Initially do not place a jaxb.index file with your Sample.java, this way you will see the JaxbException. After you see that you get the JaxbException, then place an jaxb.index file with your Sample.java, and rebuild your project. The second time around, once you have an jaxb.index file, your JAXBException will eliminated.
The test case uses a schema file named: sample.xsd, this is created using Sun's schemagen tool that comes with Java. From the command line: schemagen path/Sample.java. This creates a file named schema1.xsd, rename this file and copy to your test project folder. For detailed info see: Sun JAXB Tutorial
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement
public class Sample {
@XmlElement(name = "value")
private String val;

public Sample() {
}

public Sample(String val) {
this.val = val;
}

public String getVal() {
return val;
}

public void setVal(String val) {
this.val = val;
}

@Override
public String toString() {
return "Sample [val=" + val + "]";
}
}
This test case below tests both Marshalling and Unmarshalling using Jaxb.
public void testGenerateMarshallerToFile() throws JAXBException, FileNotFoundException, SAXException
{
JAXBContext context1 = JAXBContext.newInstance(Sample.class);

JAXBContext context2 = JAXBContext.newInstance("com.acme.businessobjects");

Marshaller m = context1.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
Sample sample = new Sample();
sample.setVal("Hello");
final File f = new File("src/test/java/com/endurotracker/gwt/test/rest/api/sample.xml");
m.marshal(sample, new FileOutputStream(f));

Unmarshaller um = context2.createUnmarshaller();

um.setSchema(getSchema("Sample.xsd"));

Object bce = um.unmarshal(f);

m.marshal(bce, System.out);



}
To test your Restlet web services with Jaxb, you will need to create a SampleResource class. Luckily, for you there is such a test in the org.restlet.test package, so you will only need to download the latest restlet source code. restlet.org The name of the test class you are interested in is: JaxbIntegrationConverterTestCase

Friday, January 1, 2010

Restful Web Services using Asp.net MVC

Microsoft's new Asp.net MVC framework can also easily support Restful Web Services.
Controller actions can be called from Ajax based based websites using Javascript.
For example if you create a controller named APIController with a method:GetUsers,
then a Restful url would be /API/GetUsers. To implement your Restful Web Services using Asp.net MVC, take a look at these excellent write ups,
create-rest-api-using-asp-net-mvc-that-speaks-both-json-and-plain-xml, and
Creating-a-RESTful-Web-Service-Using-ASPNet-MVC-Part-1-Introduction