Webservices using JAXB and JAX-WS Lalit Bhatt SpiderLogic .

Webservices using JAXB and JAX-WS

Lalit Bhatt SpiderLogic

http://www.spiderlogic.com

http://www.spiderlogic.com/



JAXB JAX-WS

© www.spiderlogic.com

Agenda

Provides binding between XML and Java To provide a higher level of abstraction to work with. Associates a set of Java classes with XML. Think of Java class as representing the XML instances.

Reference site: https://jaxb.dev.java.net


JAXB – Java XML binding

https://jaxb.dev.java.net/


JAXB in Action – Dev time

XML schemaJAXB

Compiler

Schema derivedClasses and

interface

XML schemaJAXB

Schemagenerator

Java classes


JAXB in Action – Run time

XML document JAXB API

Java objects representing XML content

unmarshel

marshel

Demo


JAXB

Advantages Ease of Use. Object oriented way of doing things.

Disadvantages Abstraction has a cost


JAXB

Understanding how JAX-WS can be used to implement SOAP based web services both at server and client side.


JAX-WS

Dave Podnar's Five Stages of Dealing with Web Services

Denial - It's Simple Object Access Protocol, right?Over Involvement - OK, I'll read the SOAP, WSDL, WS-I BP, JAX-RPC, SAAJ, JAX-P... specs. next, I'll check the Wiki and finally follow an example showing service and client sides.Anger - I can't believe those #$%&*@s made it so difficult!Guilt - Everyone is using Web Services, it must be me, I must be missing something.Acceptance - It is what it is, Web Services aren't simple or easy


Webservices

Web service is about SOAP, WSDL and UDDI – Web service is higher level concept than this. SOAP, WSDL and UDDI are actually implementation details.

Web services are based on RPC paradigm – Web services are document driven also.

Web services are based on HTTP – Web services can work on many other protocols like SMTP.

Web services can cure cancer


Webservices

XML XSDXSLT Xpath JAXP

SAX DOM JAXB StaXSOAP WSDL UDDI RestJAX-RPC JAX-WS JAX-RS

SAAJ WS* BPAxis Metro

ESBSOA


Jargons Jargons


Webservice

Client

Web service details – WSDL on XML

Request - SOAP on XML

Reposnse – SOAP on XML

Invoked initially

Invoked whenever messageexchange happens

Server

Plain old Java Object (POJO) can be easily exposed as web service.

Annotation driven

Data binding through JAXB

Server Independent


Webservice – JAX-WS way

Write the class

Annotate

Register in web.xml

Deploy – The server runtime willGenerate and publish WSDL.Map SOAP request to a Java method invocation.Translate method return into a SOAP response


JAX-WS Servlet way

@WebServicepublic class TemperatureConverter {

@WebMethod public double celsiusToFarenheit(double temp){

... }

@WebMethod public double farenheitToCelsius(double

temp){ ...

}

}


JAX-WS Servlet way

<servlet> <servlet-name>tempConv</servlet-name> <servlet-class> com.lalit.TemperatureConverter </servlet-class></servlet>

<servlet-mapping> <servlet-name>tempConv</servlet-name> <url-pattern>/tempConv</url-pattern></servlet-mapping>


JAX-WS Servlet way


JAX-WS Servlet way

`

CLIENTt

1. Get WSDL WSDL PublishedOn Server

End

poin

tLi

stener

Disp

atch

er

HandlerChain

SOAPFault

Processing

JAX

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appin

g

Web S

erv

iceJa

va e

ndpoin

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2. SOAP request 3 4 65

10 9 8 711. SOAP resp

Annotate

Deploy ejb jar


JAX-WS EJB3 way

@Stateless@WebServicepublic class TemperatureConverter {

//Rest code remains same.


JAX-WS EJB3 way

Starting Java 6

Generate the artifact using wsgen tool.

wsgen tool generates JAXB mapped classes

Use embedded HttpServer to deploy the webservice


JAX-WS Java SE Endpoint

public static void main(String[] args) {

TemperatureConverter tc= new

TemperatureConverter();

//Java comes with an embedded Http server//which is used to host the serviceEndpoint endpoint = Endpoint.publish

("http://localhost:8080/tempConv", tc);

//Keeping commented, keeps the server running

/*endpoint.stop();*/ }


JAX-WS Java SE Endpoint

Generate artifact using wsimport pointing to WSDL

wsimport generates JAXB binding classes and service endpoint

Call the web service using service end point


JAX-WS Client side

//Make the instance of service classTemperatureConverterService service =

new TemperatureConverterService();

//Get port to invoke webserviceTemperatureConverter port = service.getPort (TemperatureConverter.class);

//Call the web service.double fahr = port.celsiusToFarenheit(100);


JAX-WS Client side

JAX-WS supports start from WSDL approach

@WebService (name = "TemperatureConvertor", endpointInterface= "com.lalit.ws.TemperatureConvertor", targetNamespace = "http://ws.crayom.com/", wsdlLocation = "WEB-INF/TemperatureConvertorDocStyle.wsdl")public class TemperatureConvertorService implements TemperatureConvertor {


JAX-WS start From WSDL

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 followingProvider<Source>Provider<SOAPMessage>Provider<DataSource>.


JAX-WS Provider

@WebServiceProvider ( serviceName = "TempConvProvider",

portName="TempConvPort", targetNamespace = "http://www.crayom.com/om", wsdlLocation=

"WEB-INF/wsdl/TempConvProvider.wsdl")@ServiceMode(value=Service.Mode.PAYLOAD)public class TempConvProvider implements Provider<Source>{

public Source invoke(Source request) { … return resp;

}}


JAX-WS Provider

PAYLOAD gives the body of message.MESSAGE will give whole SOAP

Message

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


JAX-WS Dispatch

Service service = Service.create(url, serviceName);

Dispatch<Source> sourceDispatch = service.createDispatch(portQName,

Source.class,

Service.Mode.PAYLOAD);

//request is a XML which is put into SOAP payload StreamSource streamSource = new StreamSource

(new StringReader(request)); Source result = sourceDispatch.invoke(streamSource);


JAX-WS Dispatch

JAX-WS provides support for SOAP fault handling in terms of exceptions.

JAX-WS supports handlers both on client and server side , which can process SOAP headers. SOAP headers are used to build Quality of services (QOS).

JAX-WS supports asynchronous communication


JAX-WS Apart From this

Thanks

Lalit Bhatt (http://www.lalitbhatt.com)SpiderLogic (http://www.spiderlogic.com )

http://www.lalitbhatt.com/


Webservices using JAXB and JAX-WS Lalit Bhatt SpiderLogic .

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