Developing RESTful WebServices using Jersey

RESTful Web services using Java

About Web service

• What is Web service?

• What is WSDL?

• What is SOAP?

WSDL Structure
<definitions>
<types>
definition of types........
</types>
<message>
definition of a message....
</message>
<portType>
definition of a port.......
</portType>
<binding>
definition of a binding....
</binding>
</definitions>

SOAP Sample
POST /StockQuote HTTP/1.1
SOAPAction: "Some-URI“

<soapenv:Envelope xmlns:soapenv="......">
<soapenv:Header/>
<soapenv:Body>
<it:GetEmployeeName>
<it:ID>4118830901957010</it:ID>
</it:GetEmployeeName>
</soapenv:Body>
</soapenv:Envelope>

Have you ever wondered why
here is so much overhead in
designing a simple web service
like ‘GetEmployeeName’ using
SOAP?

REpresentational State Transfer
(REST)

• REpresentational State Transfer

• What is JAX-RS?

• What is Jersey?

REST Concepts
• Resources (nouns)
– Identified by a URI, For example:
http://www.parts-depot.com/parts

• Uniform interface (verbs)
– Small fixed set:
Create, Read, Update, Delete

• State Representations
– data and state transferred between client and server
XML, JSON, Atom, XHTML, ...

JAX-RS Introduction
• Set of Java APIs for development of
web services built according to the REST
principals
• Annotations
• Jersey is the open source , production quality,
JAX-RS (JSR 311) Reference Implementation
for building RESTful Web services.
• Jersey Homepage
https://jersey.dev.java.net/

Sample RESTful Web service
@Path("/helloworld/{name}")
public class HelloworldResource {
@Context
private UriInfo context;

/** Creates a new instance of HelloworldResource */
public HelloworldResource() {
}

/**
* Retrieves representation of an instance of jaxrstest.HelloworldResource
* @return an instance of java.lang.String
*/
@GET
@Produces("text/plain")
public String sayHello(@PathParam("name") String name,
@DefaultValue("HR") @QueryParam("dep") String department) {
return "Hi "+name+" Welcome to "+ department +" department";
}

@GET
@Path("/sunresource")
public String testSubResource(){
return "This is from Sub Resource";
}

/**
* PUT method for updating or creating an instance of HelloworldResource
* @param content representation for the resource
* @return an HTTP response with content of the updated or created resource.
*/
@PUT
@Consumes("text/plain")
public void putText(String content) {
System.out.println("======"+content+"=====");
}

}

Examples on the web
• Google AJAX Search API
– http://code.google.com/apis/ajaxsearch/
• Amazon S3
– http://aws.amazon.com/s3
• Services exposing Atom Publishing Protocol or GData
– i.e. Google apps like Google Calendar
• Accidentally RESTful
– Flickr, Del.icio.us API

REST Framework alternatives
• Restlet (opensource client and server API)
– http://www.restlet.org/
• CXF
– HttpBinding
– JAX-WS Provider/Dispatch API
• Axis2
– HttpBinding (WSDL 2.0)
• JAX-RS

For More Information
• BOF-5613 - Jersey: RESTful Web Services Made Easy
• Official JSR Page
> http://jcp.org/en/jsr/detail?id=311
• JSR Project
> http://jsr311.dev.java.net/
• Reference Implementation
> http://jersey.dev.java.net/
• Marc's Blog
> http://weblogs.java.net/blog/mhadley/
• Paul's Blog
> http://blogs.sun.com/sandoz/
• Jakub's Blog
> http://blogs.sun.com/japod/

Developing RESTful WebServices using Jersey

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Developing RESTful WebServices using Jersey