Java Platform Enterprise Edition Java EE

1
Java Platform Enterprise Edition (Java EE)
Introduction to Java EE 5 Technologyhttp//www.ne
tbeans.org/kb/55/javaee-intro.html Java EE 5
Tutorialhttp//cs.uccs.edu/cs301/javaeetutorial5
/doc/
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Introduction to Java EE

• We will cover
• Java EE 5 Web Services
• Java Persistence API
• NetBean5.5 is used as IDE
• Sun Application Server 9 is used as application
  server.
• See http//cs.uccs.edu/cs301/netbean/netbean5_5t
  ut.html for detailed installation instructions
  with corrections on tutorial exercises.

3
Annotation vs. Deployment Descriptors

• In J2EE 1.4, for enterprise java beans and web
  services, we need to specify the related
  deployment descriptors, ejb-jar.xml and web.xml.
• They are too complicated and easy to make
  mistake. JEE 5 replace them with Annotation.
• Annotations are Java modifiers, similar to public
  and private, specified in Java code. (better
  integration)
• EJB 3 specification and JAX-WS 2.0 specify the
  sets of annotations for EJB and WS.
• Others specify
• the mapping of Java classes to database (Java
  Persistence)
• the mapping of Java classes to XML.
• Security attributes

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Example of Annotation

• package mypackage import javax.ejb.
• _at_Stateless() //Stateless session beanpublic
  class HelloWorldSessionBean implements
  mypackage.HelloWorldSessionLocal
• _at_Entity // when create Animal as entity class in
  Persistence Categories
• public class Animal implements Serializable
• _at_Id // each entity class must have a
  primary key
• _at_GeneratedValue(strategy GenerationType.AUTO
  )
• private Long id
• _at_Column(name"animalName") // change column
  name to animalName
• private String name
• private String kind
• private String weight
• _at_ManyToOne // specify many-to-one
  relationship.
• private Pavilion pavilion

5
Java Persistence in JEE5

• Follow the tutorial in http//www.netbeans.org/kb/
  55/persistence.html
• Estimated about 15min.
• It illustrates
• The use of Java Persistence API. Use
  Oracle.TopLink Essential.jar as Persistence
  Provider.
• The use of annotation.
• The use of Refractor gt Encapsulate fields (save
  tremendous coding effort!!)
• The use of Entity Class wizard to add Java Server
  Faces (JSF) pages to the application.

6
Motivation for Service Oriented Architecture
(SOA)

• There is an increase trend for sharing
  resource/data both within companies and among
  companies in a flexible/standardized manner.
• In a service oriented approach, the complete
  value chain within the company is divided into
  small modular functional units, or services.
• A service oriented architecture focus on how
  services are described and organized to support
  the dynamic, automated discovery and use.
• Companies and their sub-units should be able to
  easily provide services. Other business units can
  use these services in order to implement their
  business processes.

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Service-Oriented Architecture

• Consists of three basic components
• Service provider
• Service broker (aka service registry)
• Service requestor

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Requirements of SOA

• Interoperability between different systems and
  programming languages. (Use standards platform
  independent)
• Clear and unambiguous description language
• Retrieval of the service
• Security

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What is Web Services

• A Web Service is a software component that is
  described via WSDL and is capable of being
  accessed via standard network protocols such as
  but not limited to SOAP over HTTP---www.oasis-ope
  n.org/committees/wsia/glossary/wsia-draft-glossary
  -03.htm
• Web services are self-contained, modular
  applications that can be described, published,
  located, and invoked over a network IBM Redbook.
• The Web technologies used
• XML (Extensible Markup Language)
• SOAP (Simple Object Access Protocol) allow client
  to call remote service. The msg format is XML.
• WSDL (Web Services Description Language)
• WSIL (Web Services Inspection Language)
• UDDI (Universal Description, Discovery, and
  Integration) a standard used for publishing/query
  web services
• Web Services can be used to realized service
  oriented architecture.

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Short History of Web Services

• HTTP protocol facilitates Human-to-Application
  (H2A) communications.
• There is an increasing demand for
  Application-to-Application communication using
  existing techniques.
• HTTP is not adequate for more complex operations.
  E.g., remote operation
• Late 1999, Microsoft published SOAP an XML-based
  protocol.
• IBM supports SOAP early 2000.
• May 2000 W3C Note SOAP 1.1.
• The term Web services was coined several months
  later, when IBM, Microsoft, and Ariba jointly
  published the Web Services Description Language
  (WSDL).
• March 2001 W3C Note WSDL1.1
• 2002, UDDI 1.0 (API 6/28 UDDI v1.0 XML schema
  WSDL Service Interface Description UDDI Inquire
  API/UDDI Publish API) were also introduced, thus
  completing the set of standards and protocols
  that make up the basis of Web services.

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Current Web Service Standards

• 9/19/2005 Web Services Description Language
  (WSDL) Version 2.0 Part 0 Primer (W3C Candidate
  Recommendation 27 March 2006)
• 2/3/2005 UDDI v3.0 Ratified as OASIS standard.
• June 2003 SOAP Version 1.2 released as a W3C
  Recommendation
• 2/21/2006 Oasis Web Service Security (WSS)1.1
  formal standard. Address Quality of Service (QoS)
  and Security issues.
• There are more than 40 specifications and
  standards published!

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SOA based on Web Services
13
Java Web Services

• JSR 224, Java API for XML-Based Web Service
  (JAX-WS) 2.0.
• New in JEE 5 replace JAX-RPC 1.1
• Support SOAP 1.1, 1.2, and XML/HTTP protocols.
• Support additional protocols FAST-Infoset
  MTOM/XOP (short for message transmission
  optimization mechanism/XML-binary optimized
  packaging) for attachments with large binary
  data
• JSR 222, Java Architecture for XML Binding (JAXB)
  2.0
• JAXB can generate XML Schema document to be
  embedded inside WSDL. XML Schema does not have to
  be manually generated. Reduce errors.
• JSR 181, Web Services Metadata for Java Platform

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Java Web Services New Features

• Specify with annotation _at_WebService, not long
  unwieldy descriptors.
• All the public methods on the class are
  automatically published as web service operations
• All their arguments are mapped to XML Schema data
  types using JAXB 2.0.

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Asynchronous Web Services

• JAX-WS 2.0 provides new Asynchronous Client API
  so that interactive clients performance will not
  be degraded when waiting for servers response.
• Client does not need to create threads on their
  own.
• JAXS-WS runtime manages long-running remote
  invocations.
• When importing a WSDL document, can require
  asynchronous methods to be generated for any of
  the operations defined by the web service.
• Two usage models
• Polling model make a call. When you're ready,
  you request the results.
• Callback model register a handler. As soon as
  the response arrives, you are notified.

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JAX-WS tutorial in NetBean5.5

• http//www.netbeans.org/kb/55/websvc-jax-ws.html
• Use NetBean 5.5 to create a JAX-WS web service,
  and three clients (Java SE app, servlet, JSP
  page) to access the web service.
• Expected duration 25min
• For Testing CalculatorWS directly when run
  project from NetBean5.5, I got 404 The requested
  resource () is not available.
• To get around theat, we can login to admin web
  page http//localhost4848/asadmin/admingui/TopFra
  meset
• From admin console, click the CalculatorWS under
  Web Services and then click on the test button on
  the right panel. The tester web page will appear.
• I found if enter 20 with space after 20,
  instead of 20. It triggers java.lang.IllegalArgu
  mentException!!

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Access Web Service from a Java Application

• public static void main(String args)
• try // Call Web Service Operation
• org.me.calculator.client.CalcultorWSServ
  ice service new org.me.calculator.cl
  ient.CalcultorWSService()
• org.me.calculator.client.CalcultorWS
  port service.getCalcultorWSPort()
• int result port.add(3, 4)
• System.out.println("Result
  "result)
• catch (Exception ex)
• System.err.println(Error accessing
  web serviceex.toString)
• // note that all code here generated by
  
• //Choose Web Service Client Resources gt
  Call Web Service Operation.

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Access Web Service from Java Servlet

• public class ClientServlet extends HttpServlet
• _at_WebServiceRef(wsdlLocation
  "http//localhost8080/CalculatorWSApplication/Cal
  cultorWSService?wsdl")
• private org.me.calculator.client.CalcultorWSSe
  rvice service
• // note that service is defined different
  than that in tutorial
• protected void processRequest(HttpServletReque
  st request, HttpServletResponse response)
• throws ServletException, IOException //
  process request for both GET and POST
• response.setContentType("text/htmlcharset
  UTF-8")
• PrintWriter out response.getWriter()
• out.println("lth1gtServlet ClientServlet at
  " request.getContextPath () "lt/h1gt")
• try // Call Web Service Operation
• org.me.calculator.client.CalcultorWS
  port service.getCalcultorWSPort()
• int result port.add(3, 4)
• out.println("Result "result)
• catch (Exception ex)
• // TODO handle custom exceptions here

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Access Web Service from JSP

• lt_at_page contentType"text/html pageEncoding"UTF-8
  gt
• lt!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01
  Transitional//EN"
• "http//www.w3.org/TR/html4/loose.dtd"gt
• lthtmlgtltbodygtlth1gtJSP Pagelt/h1gt
• lt
• try
• org.me.calculator.client.CalcultorWSService
  service new org.me.calculator.client
  .CalcultorWSService()
• org.me.calculator.client.CalcultorWS port
  service.getCalcultorWSPort()
• int result port.add(3, 4)
• out.println("Result "result)
• catch (Exception ex)
• // TODO handle custom exceptions here
• gtlt/bodygtlt/htmlgt

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Asynchronous JAX-WS Web Service

• http//www.netbeans.org/kb/55/websvc-jax-ws-asynch
  .html Tutorial Example 45min
• Design the User Interface Section
• For setting the variable name of JTextField,
  select the Code tab reveals the Variable Name
  properties. It is not under Properties tab.
• For JProgressBar, stringPainted property just
  click the square box for selecting the checked
  symbol. That is enabled
• In Extending and Distributing the Application
  Section, Adding the User Interface and Businees
  Subsection, Step 5, we should click
  AsyncWSClientTopComponent.java (right next to the
  Bundle.properties window) to get the UI design
  window to appear. It is very vague for them to
  say redo steps 2 and 3.
• Cannot found JAX-WS-JARS