This document provides an overview of Java APIs for XML web services, including JAX-RPC and JAX-WS. It discusses the Java Web Services Development Pack (JWSDP) and its components like JAXP, JAXB, SAAJ. It then describes specific APIs like JAX-RPC, JAX-WS, JAXR. It also discusses the server-side and client-side programming models in JAX-WS including using annotations and generating code from WSDL.

1. Topic 4
Java API for XML Web Services
Assoc.Prof. Dr. Thanachart Numnonda
www.imcinstitute.com
August 2010

2. Agenda
 Java APIs for Web Services
 JAX-RPC
 JAX-WS
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3. Java APIs for Web Services
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4. JWSDP
 Java Web Services Development Pack (JWSDP) is a free
software development kit (SDK) for developing Web
Services
 JWSDP has been replaced by GlassFish and WSIT and
several components are in Java SE 6.
 JWSDP APIs
 Java API for XML Processing (JAXP), v 1.3
 Java Architecture for XML Binding (JAXB), v 1.0 and 2.0
 JAX-RPC v 1.1
 JAX-WS v 2.0
 SAAJ (SOAP with Attachments API for Java)
 Java API for XML Registries (JAXR)
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5. Java API for XML Processing (JAXP)
• JAXP enables applications to parse, validate and
transform XML documents.
• Java developers can invoke
• SAX parser
• DOM parser
• The main JAXP APIs are defined in the
javax.xml.parsers package
• SAXParserFactory
• DocumentBuilderFactory
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6. Java API for XML Binding (JAXB)
• JAXB allows Java developers to access and process XML data
without having to know XML or XML processing.
• JAXB is a Java technology that enables you to generate Java
classes from XML schemas by means of a JAXB binding
compiler.
• unmarshalling
• XML instance documents into Java content trees
• marshalling
• Java content trees back into XML instance documents.
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7. SAAJ (SOAP with Attachments
API for Java™)
• SAAJ provides a convenient API for constructing
and sending SOAP messages without having to
directly create the XML yourself.
• SAAJ was originally part of the Java API
for XML Messaging (JAXM) Separated out from
JAXM 1.0 into JAXM 1.1 and SAAJ 1.1
(SAAJ 1.3 (Java EE 5))
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8. JAXR
• Standard Java API for performing registry operations
over diverse set of registries
Web service publication & discovery
• A unified information model for describing business
registry content
• Provides multi-layered API abstractions
Level 0: for UDDI
Level 1: for ebXML registry/repository
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9. JAX-RPC
• XML data types to/from Java types mapping
• SOAP Message Handler framework
• WSDL to/from Java mapping
• Servlet-based Web service endpoint model
• JAX-RPC Client Programming Models
• Extensible type mapping
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10. JAX-WS (JAX-RPC 2.0)
• New handler framework
• Metadata-based Web services
• Operational style improvement
• Asynchronous Web services
• Support for non-HTTP transport
• Interoperable attachments (as part of WS-I)
• Secure Web services (as part of Security)
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11. JAXM
• JAXM is not part of Java EE 5
• JAXM-based asynchronous messaging on Java EE 5
is supported via
Message-driven Bean (MDB) in EJB 3 can receive
both JMS and JAXM message types
Connector 1.5 allows pluggability of various types
message providers (JAXM provider and JMS
provider)
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12. Java APIs for Web Services Protocols
 SOAP
 JAXM 1.0 (JSR 67), SAAJ
 JAX-RPC => JAX-WS 2.0 (JSR 224)
 WSDL
 JAX-RPC => JAX-WS 2.0 (JSR 224)
 UDDI
 JAXR 1.0 (JSR 93)
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13. Sun’s Web Services Stack
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14. JAX-RPC
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15. Remote Procedure Call (RPC)
Request
Response
Client System Server System
 RPC, COM, CORBA, RMI:

Synchronous communication: calling process blocks until
there is a response

More tightly coupled (than non-RPC model): client must
find recipients and know method and its arguments

Non persistent

16. Remote Procedure Calls
Client Interface Interface Servant
Stub Skeleton
Run Time Protocol Run Time

Common Interface between client and Server

Stub for client, Skeleton/Tie for server

On-the-wire protocol needs to be agreed upon

17. RPC Example – Java RMI
<<Interface>>
Java Remote
Interface
rmic compiler
Client Remote Object
Implementation
RMI Client RMI Server
Stub Skeleton
Java Remote Method Protocol (JRMP) is
On-the-wire protocol

18. RPC Example - JAX-RPC

19. Common Interface
 Service is described in IDL (Interface Description
Language)
 IDL ofCORBA service
 Java RMI interface in RMI (Language specific)
 WSDL for Web service
 Used by tools to statically or dynamically generate
and/or configure interfaces, proxies, and ties in a
network technology specific environment

20. What is JAX-RPC?
 Java™ API for XML-based RPC
 Web Services operations are performed by exchanging
SOAP 1.1 messages
 Services are described using WSDL
• WSDL is the contract between service provider and
client (only contract needed)
 Web service endpoints and clients use JAX-RPC
programming model
 Key technology for Web Services in the J2EE 1.4
platform

21. JAX-RPC Design Goals
 Easy to use programming model
• For both defining & using a service
 Hides all the plumbing
• You don't have to create SOAP messages yourself
 SOAP and WSDL-based interoperability
• Interoperate with any SOAP 1.1 compliant peers
 Extensibility and Modularity
• Support new versions of XML specification, i.e. SOAP 1.2
and beyond
• Message handler architecture

22. JAX-RPC Architecture
JAX-RPC JAX-RPC
Client WSDL Document Service Endpoint
Generated JavaWSDL WSDLJava
Code
Container Container
Client-side JAX-RPC Server-side JAX-RPC
Runtime System Runtime System
SOAP
HTTP

23. JAX-RPC Runtime System
 Core of a JAX-RPC implementation:
• Library that provides runtime services
for JAX-RPC mechanisms
• Implements some of the JAX-RPC APIs
 Client side:
• Can be implemented over J2SE™, J2EE™ or J2ME™
platforms
 Server-side:
• J2EE 1.3 or 1.4 Containers: EJB™ or Servlet

24. Developing a Web Service
Interfaces (java.rmi.Remote type)
Must follow JAX-RPC conventions
Implementation classes
Servlet-based endpoint model
Optional handler and serializer classes
tool
WSDL Service contract
Packaged application (war file)

25. JAX-RPC : Web Service Endpoint
JAX-RPC
Service Endpoint
WSDL<-->Java
WSDL Document Container
Server-Side
JAX-RPC
Runtime
System
SOAP
HTTP

26. JAX-WS
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27. Quick overview of JAX-WS
 Easy way to use Java API for XML Web Services
 Replace JAX-RPC
 Just add @annotation to POJO
 XML Descriptor free programming
 Layer architecture
 SOAP 1.2 (Document/Literal)
 Use JAXB for data binding
 Protocol and transport independence
 Part of Java SE6 and Java EE 5 Platform
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28. JAX-WS Layered Architecture
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29. What Does It Mean?
• Upper layer uses annotations extensively
• Easy to use
• Great toolability
• Fewer generated classes
• Lower layer is more traditional
• API-based
• For advanced scenarios
• Most application will use the upper layer only
• Either way, portability is guaranteed
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30. Two ways to create a Web Service
• Starting from a WSDL file
> Generate classes using wsimport (=> xjc)
> WS interface
> WS implementation skeleton class
> Implement WS interface
> Build and deploy
• Starting from a Java class (POJO)
> Annotate POJO
> Build and deploy
> WSDL file generated automatically
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31. Start with a Java Class
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32. Server-Side Programming Model: POJO
1 Write a POJO implementing the service
2 Add @WebService annotation to it
3 Build and Deploy the application
WSDL is automatically generated at runtime
1 Point your clients at the WSDL
e.g. http://myserver/myapp/MyService?WSDL
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33. Example 1: Servlet-Based Endpoint
@WebService
public class Calculator {
public int add( int a, int b) {
return a + b;
}
}
• @WebService annotation
• All public methods become web service operations
• WSDL/Schema generated automatically
• Default values are used
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34. Service Description Default Mapping
• Java mapping => WSDL
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35. Example 2: EJB-Based Endpoint
@WebService
@Stateless
public class Calculator {
public int add( int a, int b) {
return a + b;
}
}
• It’s a regular EJB 3.0 component, so it can use any
EJB features
> Transactions, security, interceptors...
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36. Customizing through Annotations
@WebService(name=”CreditRatingService”,
targetNamespace=”http://example.org”)
public class CreditRating {
@WebMethod(operationName=”getCreditScore”)
public Score getCredit(
@WebParam(name=”customer”)
Customer c) {
// ... implementation code ...
}
}
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37. Start with a WSDL file
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38. Generating an interface from WSDL
• WSDL => Java generation
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39. Implementing a Web Service from
a Generated Interface
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40. Server Side Web Service
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41. JAX-WS uses JAXB for Data Binding
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42. add() Parameter : Example
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43. JAXB XML Schema to Java Mapping
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44. Client Side Programming
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45. Java SE Client Side Programming
• Point a tool (NetBeans or wsimport) at the WSDL
for the service
wsimport http://example.org/Calculator.wsdl
• Generate annotated classes and interfaces
• Call new on the service class
• Get a proxy using a get<ServiceName>Port method
• Invoke any remote operations
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46. Example : Java SE-Based Client
CalculatorService svc = new CalculatorService();
Calculator proxy = svc.getCalculatorPort();
int answer = proxy.add(35, 7);
• No need to use factories
• The code is fully portable
• XML is completely hidden from programmer
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47. Java EE Client Side Programming
• Point a tool (NetBeans or wsimport) at the WSDL
for the service
wsimport http://example.org/calculator.wsdl
• Generate annotated classes and interfaces
• Inject a @WebServiceReference of the
appropriate type
• No JNDI needed
• Invoke any remote operations
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48. Example : Java EE-Based Client
@Stateless
public class MyBean {
// Resource injection
@WebServiceRef(CalculatorService.class)
Calculator proxy;
public int mymethod() {
return proxy.add(35, 7);
}
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49. Client Side
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50. Annotations Used in JAX-WS
• JSR 181: Web Services Metadata for the
Java Platform
• JSR 222: Java Architecture for XML
Binding (JAXB)
• JSR 224: Java API for XML Web Services
(JAX-WS)
• JSR 250: Common Annotations for the
Java Platform

51. @WebService
• Marks a Java class as implementing a
Web Service, or a Java interface as
defining a Web Service interface.
• Attributes
> endpointInterface
> name
> portName
> serviceName
> targetNamespace
> wsdlLocation

52. @WebMethod
• Customizes a method that is exposed as
a Web Service operation
• The method is not required to throw
java.rmi.RemoteException.
• Attributes
> action
> exclude
> operationName

53. @WebParam
• Customizes the mapping of an individual
parameter to a Web Service message
part and XML element.
• Attributes
> header
> mode
> name
> partName
> targetNamespace

54. @WebResult
• Customizes the mapping of the return
value to a WSDL part and XML element.
• Attributes
> header
> name
> partName
> targetNamespace

55. JAX-WS - Provider
• Web Service endpoints may choose to work at
the XML message level by implementing the
Provider interface.
• The endpoint accesses the message or
message payload using this low-level, generic
API
• Implement one of the following
> Provider<Source>
> Provider<SOAPMessage>
> Provider<DataSource>

56. JAX-WS - Provider

57. JAX-WS - Dispatch
• Web service client applications may choose to
work at the XML message level by using the
Dispatch<T> APIs.
• The javax.xml.ws.Dispatch<T> interface
provides support for the dynamic invocation of
service endpoint operations.
• Similar to Provider on server side

58. JAX-WS - Dispatch

59. Resources
 Some contents are borrowed from the presentation
slides of Sang Shin, Java™ Technology Evangelist,
Sun Microsystems, Inc.
 Web Services and Java, Elsa Estevez, Tomasz
Janowski and Gabriel Oteniya, UNU-IIST, Macau
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60. Thank you
thananum@gmail.com
www.facebook.com/imcinstitute
www.imcinstitute.com
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