- JAX-RS and Jersey provide Java APIs for building RESTful web services using annotations to define resource endpoints and HTTP methods. This avoids complex XML configuration compared to earlier technologies like SOAP and Apache Axis. - Jersey is an open source framework that implements JAX-RS and allows defining root resource classes and mapping them to URLs to build RESTful web service applications. It supports object serialization formats like JSON and handles request/response processing. - The presentation covers the evolution of web service technologies, how JAX-RS and Jersey address issues with earlier approaches using annotations, and features of Jersey like resource lifecycles, WADL generation, and client APIs.

1. JAX-RS & JERSEY
Yung-Lin Ho <yho@bluetangstudio.com>
founder of blue tang studio

2. ABOUT ME
• Yung-Lin Ho. AKA HYL.
• founder of blue tang studio
• Working on Location Based Platform
• Cassandra / Zookeeper
• Lucene
• Tapestry / Jersey
• Scala !

3. WEBSERVICE IN YEAR 2000
• Servlet API
• public void doGet(HttpServletRequest request, HttpServletResponse response) {
String name = request.getParameter(“name”);
NameParameterValidator.validate(name);
Object resObj = requestProcessor.process(name);
Serializer ser = ObjectSerializerFactory.getSerializer(request.getParameter(“format”))
ser.write(resObj, response);
}
• Struts
• Action, Validator, Processor...

4. YEAR 2005
• SOAP, Apache Axis, Apache CXF
• XML configuration HELL.
• no compile time check.
• keep code and configuration in-sync.

5. OPEN SOURCE WORLD
• Restful Requests
urlpatterns = patterns('',
(r'^articles/2003/$', 'news.views.special_case_2003'),
(r'^articles/(?P<year>d{4})/$', 'news.views.year_archive'),
(r'^articles/(?P<year>d{4})/(?P<month>d{2})/$', 'news.views.month_archive'),
(r'^articles/(?P<year>d{4})/(?P<month>d{2})/(?P<day>d+)/$',
'news.views.article_detail'),
)
• Rest won the battle. SOAP started to fad.
• why?

6. ANNOTATION COME TO RESCUE
@Path("/rest/1.0/model/{modelId}")
@Produces({"application/json"})
public interface DataService {
@GET
@Path("/doc/{docId}")
public Document get(@PathParam(“modelId”) UserModelId modelId,
@PathParam("docId") DocumentId documentId);
@PUT
@Path("/doc/{docId}")
@Consumes({"application/json"})
public void saveOrUpdate(@PathParam(“modelId”) UserModelId modelId
@PathParam("docId") DocumentId documentId,
Document document);
@DELETE
@Path("/doc/{docId}")
public void delete(@PathParam(“modelId”) UserModelId modelId
@PathParam("docId") DocumentId documentId);
}

7. URL AND PATTERN MATCHING
• @Path("/rest/1.0/model/{modelId}")
• @GET, @POST, @PUT, @DELETE, @HEAD
• @PathParam, @QueryParam, @FormParam, @HeaderParam,
@CookieParam and @MartixParam
• @DefaultValue

8. OBJECT SERIALIZATION
• @Produce & @Consume
• POJO, JAXB, Jackson-Json.
@XmlRootElement
{"name":"Agamemnon", "age":"32"}
public class MyJaxbBean {
public String name;
public int age;
public MyJaxbBean() {} // JAXB needs this
public MyJaxbBean(String name, int age) {
this.name = name;
this.age = age;
}
}

9. FINALLY. JERSEY.
• what is jersey - a servlet javax.ws.rs.core.Application
• ways to contributes RootResource(s) to Application.
<servlet>
<servlet-name>Jersey Web Application</servlet-name>
<servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>com.sun.jersey.config.property.packages</param-name>
<param-value>org.foo.rest;org.bar.rest</param-value>
</init-param>
</servlet>
public class MyApplicaton extends Application {
public Set<Class<?>> getClasses() {
Set<Class<?>> s = new HashSet<Class<?>>();
s.add(HelloWorldResource.class);
return s;
}
}

10. ROOTRESOURCE LIFECYCLE
• New class instance for each request if you put class into
Application
• Same instance for all requests if you put class instance into
Application.

11. WADL
• @Path("/form")@ProduceMime("text/html")
public class Form {
@Path("colours")
public Colours getColours() {
return coloursResource;
}
}
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<application xmlns="http://research.sun.com/wadl/2006/10">
<resources base="http://localhost:9998/resources/">
<resource path="/form">
<method name="GET">
<response>
<representation mediaType="text/html" />
</response>
</method>
<method name="POST">
<request>
<representation mediaType="application/x-www-form-urlencoded" />
</request>
<response>
<representation mediaType="text/html" />
</response>
</method>
<resource path="colours" />
</resource>
</resources>
</application>

12. CLIENT API
• https://github.com/yunglin/common-jaxrs-client
SearchServiceClient client =
ClientFactory.getClient(
SearchServiceClient.class, endPoint, myModel);
•

13. QA