This document provides an overview of Java EE 6 web services, including RESTful and SOAP web services. It distinguishes between the two types and describes their standards (JSR 311 and JSR 224). Features of web services like platform independence and use of HTTP/XML are outlined. Benefits and disadvantages of web services are discussed, and the JAX-RS and JAX-WS APIs used for implementing RESTful and SOAP endpoints in Java are described, including annotations used. Examples of RESTful and SOAP requests/responses are also provided.

1. Java EE 6 – Web Service
Vladan Pulec

2. Objectives
 Overview
 Distinguish between the two types of web
services
 RESTful Service & Demo
 Web Service & Demo

3. Key Features
• Platform independent
• Language independent
• Interoperable across disparate programming
languages
• Leveraging existing technologies (HTTP, XML)
• Supported in SE and EE version of Java

4. Benefits
• Flexibility of supporting unknown future client
platforms
• Use of HTTP
• Easier communication via firewalls and proxies
• Flexible to use a variety of transmission
protocols (ie. SMTP)

5. Disadvantages
• Verbose (can be slower than other
middleware technologies)
• Relying on HTTP, the roles are fixed (only one
party can use the service of the other).
– Service cannot push, client must pull

6. Web Service Standards
• There are two prevailing types:
• Representational State Transfer (REST) – JSR 311
• Simple Object Access Protocol (SOAP) – JSR 224

7. RESTful Web Services
• Representation State Transfer (REST) revolve
around resources (candidate, client, etc)
• The state of the resource is captured and
transferred using the service

8. JAX-RS API
• Does not require any specific data format
• Often CSV, JSON (JavaScript Object Notation), or
XML
• Provides only server-side API
• Can be combined with JAXB or any other Java
XML API

9. Web Service Endpoints
• Remotely executable components that exist
on the server and are executed as a result of
receiving a web service request.
• Both JAX-RS and JAX-WS can use the
following:
• Annotated POJOs
• Session bean components (Stateless or Singleton
beans only)

10. JAVA-RS Endpoints
• The end point is:
• Annotated class created to provide web service
functionality
• Is instantiated per request
• Does not require an EJB container
• JAVA-RS will provide a servlet implementation
to handle the requests

11. JAVA-RS Web Endpoints
• Must have the following:
– @javax.ws.rs.Path class annotation
– Public methods that are annotated with method
designator (ie. @GET)
– Uses @Produces and/or @Consumers annotations
– Cannot be abstract
• Web.xml must have a web a JAVA-RS servlet
configured
– Classes with @Path annotation will be handled by
it.

12. REST Example
1. A resource is given a specific URL (such as
http://localhost/clients/adobe)
2. HTTP methods are used to perform operations
– HTTP GET – retrieves the resource representation
– HTTP POST – adds new element to the resource
– HTTP PUT – creates or updates resource
– HTTP DELETE – deletes the resource
• Content can be of any MIME Type (text, XML, etc.)

13. SOAP Web Services
• Simple Object Access Protocol (SOAP)
• More complex than REST but provides more
benefits
• To implement SOAP client, developer only
needs to know the Web Services Description
Language (WSDL) file, which exposes all API
information
• Utilizes HTTP request/response and XML

14. JAX-WS
• Replaces JAX-RPC
• Required minimal knowledge of XML or WSDL
to use basic services
• Provides both server and client APIssd SOAP
Client Service
JAX-WS runtime JAX-WS runtimeSOAP Message

15. Sample SOAP Request
• <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/“
xmlns:xsd="http://www.w3.org/2001/XMLSchema“ xmlns:xsi="http://www.w3.org/2001/XMLSchema-
instance">
• <SOAP-ENV:Header>
• <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-
1.0.xsd">
• <wsse:UsernameToken>
• <wsse:Username>123456</wsse:Username>
• <wsse:Password>mypassword</wsse:Password>
• </wsse:UsernameToken>
• <service_attributes ignore_warnings="false" />
• </wsse:Security>
• </SOAP-ENV:Header>
• <SOAP-ENV:Body>
• <ser:findByTestCenterID xmlns:ser="http://services.capacity.vue/">
• <testCenterID>4</testCenterID>
• </ser:findByTestCenterID>
• </SOAP-ENV:Body>
• </SOAP-ENV:Envelope>
sd SOAP
Envelope
Header
Body

16. Sample SOAP Response
• <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
• <soap:Body>
• <ns2:findByTestCenterIDResponse xmlns:ns2="http://services.capacity.vue/">
• <workstationSearchResponse>
• <testCenter id="4" name="Electronic Systems" tws="-1" />
• <workstationRules>
• <workstationRule activeRuleCount="1">
• <asset assetCategoryCode="Workstation" assetID="53412"
• assetName="Test 7" siteID="4" isEnabled="true" />
• </workstationRule>
• </workstationRules>
• </workstationSearchResponse>
• </ns2:findByTestCenterIDResponse>
• </soap:Body>
• </soap:Envelope>

17. JAVA-WS Endpoints
• Must have the following:
– @javax.jws.WebService annotation
– Public methods (cannot be final or static) with
@javax.jws.WebMethod annotation
– Class cannot be abstract or final
– Must have no args constructor

18. Data Types
• JAX-WS does not contain JAVA to XML binding
• Java Architecture for XML Binding (JAXB) is
designed to handle the binding
• Basic Java types are supported, complex ones
require JAXB programming

19. Java APIs for Web Services
JDOM – provides OO Java model of an XML document
JAXP – abstraction of an XML processing
JAXB – converts objects to XML schemas
JAX-RPC – remote access API (replaced by JAX-WS)
JAXR – standard for using UDDI registries
SAAJ – standard for transmitting and parsing SOAP messages
JAX-RS – RESTful API
JAX-WS – high-level web service API

20. Additional Resources
JSR 224 – Java API for Web Services (JAX-WS)
JSR 331 – Java API for Restful Services (JAX-RS)