Java Web Services [4/5]: Java API for XML Web Services
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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.
Java Web Services [4/5]: Java API for XML Web Services
- 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 2
- 3. Java APIs for Web Services 3
- 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Web Services Development Pack (JWSDP) is a free software development kit (SDK) for developing Web Services JWSDP has been replaced by GlassFish and WSIT and several components are in Java SE 6.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) 4
- 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 5
- 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. 6
- 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)) 7
- 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 8
- 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 9
- 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) 10
- 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) 11
- 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) 12
- 13. Sun’s Web Services Stack 13
- 14. JAX-RPC 14
- 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 JavaWSDL WSDLJava 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 26
- 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 27
- 28. JAX-WS Layered Architecture 28
- 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 29
- 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 30
- 31. Start with a Java Class 31
- 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 32
- 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 33
- 34. Service Description Default Mapping • Java mapping => WSDL 34
- 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... 35
- 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 ... } } 36
- 37. Start with a WSDL file 37
- 38. Generating an interface from WSDL • WSDL => Java generation 38
- 39. Implementing a Web Service from a Generated Interface 39
- 40. Server Side Web Service 40
- 41. JAX-WS uses JAXB for Data Binding 41
- 42. add() Parameter : Example 42
- 43. JAXB XML Schema to Java Mapping 43
- 44. Client Side Programming 44
- 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 45
- 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 46
- 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 47
- 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); } 48
- 49. Client Side 49
- 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>
- 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
- 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 59
- 60. Thank you [email protected] www.facebook.com/imcinstitute www.imcinstitute.com 60