Berner Fachhochschule. Technik und Informatik JAX-WS. Java API for XML-Based Web Services. Prof. Dr. Eric Dubuis Berner Fachhochschule Biel

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1 Berner Fachhochschule Technik und Informatik JAX-WS Java API for XML-Based Web Services Prof. Dr. Eric Dubuis Berner Fachhochschule Biel

2 Overview The motivation for JAX-WS Architecture of JAX-WS and WSDL JAX-WS Java to WSDL by example Developing a web service Developing a web service client Note: These slide are about a simple and short introduction on JAX-WS and, therefore, by no means complete. 01/29/08 JAX-WS 2

3 Why JAX-WS? Given web services, WSDL, XML, and SOAP, JAX-WS defines... how to program service endpoints in Java how to program web service clients how to program tools that generated otherwise missing intermediaries how to customize the sending and receiving of SOAP messages when using Java. JAX-WS is an industry standard. Its specification can be found here: JAX-WS defines an user API and a service provider API. We look at the user API only. 01/29/08 JAX-WS 3

4 Some Goals Being Achieved by JAX-WS Standard mapping of WSDL to Java Standard mapping of Java to WSDL (!) Standard rules for creating artifacts such as stubs and skeletons Standard rules for so-called handlers Standard way of using JAXB, another standard, which defines the Java XML binding Standard way of introducing security into web services (when using Java)... 01/29/08 JAX-WS 4

5 JAX-WS Architecture Client Application Stub / Proxy JAX-WS Runtime SOAP messages HTTP transport Service Implementation Tie JAX-WS Runtime The client invokes a stub method which is delegated to the JAX-WS runtime in order to send an appropriate SOAP message to the server On the server side, the tie converts the received message back into a method call on the actual service implementation The stub and tie classes are dynamically generated by the provider platform 01/29/08 JAX-WS 5

6 Relationship between WSDL and JAX-WS WSDL Client «use» Service Interface Service Implementation JAX-WS can generate a WSDL document from the Java implementation of a web service (code-first) JAX-WS can import a WSDL document to generate the Java code required to implement the web service (contract-first) or a web service client 01/29/08 JAX-WS 6

7 Java to WSDL Mapping A class annotated is mapped to <porttype> element Public Java methods are mapped to <operation> elements with corresponding <input> and <output> messages Java exceptions are mapped to <fault> public class StockQuoter { public double getquote(string symbol) throws NotFoundException { return ; <porttype name="stockquoter"> <operation name="getquote" parameterorder="symbol"> <input message="tns:getquote"/> <output message="tns:getquoteresponse"/> <fault name="notfoundexception" message="tns:notfoundexception"/> </operation> </porttype> 01/29/08 JAX-WS 7

8 Developing a Web Service Contract-first approach versus code-first approach A good way to get initiated into JAX-WS is to first develop a Web service. You can develop a Web service using one of two approaches: Contract first: Start with a WSDL contract, and generate a Java class to implement the service. Code first: Start with a Java class, and use annotations to generate both a WSDL file and a Java interface. The contract-first WSDL approach requires a good understanding of WSDL and XSD (XML Schema Definition) for defining message formats. It's a good idea to start with the code-first approach if you're fairly new to Web services, which is what you'll use in this introduction to develop Web services. 01/29/08 JAX-WS 8

9 Developing a Web Service 1. Define the web service endpoint interface and implement that inteface or define class 2. Compile the web service 3. Generate the portable artifacts required to deploy the service 4. Package the service code and the generated files into a web archive 5. Deploy the web archive into a running web container (additional artifacts like the WSDL document are generated) «webservice» StockQuoter NotFoundException 01/29/08 JAX-WS 9

10 Developing a Web Service Class The class must be annotated with annotation, and its method may be annotated with annotation. The methods must have JAXB compatible parameters and return types [JAX_WS, = StockQuoter, targetnamespace = ) public class StockQuoter public double getquote(string symbol) throws NotFoundException {... return...; // properties: optional // optional 01/29/08 JAX-WS 10

11 Developing a Web Service Client 1. Generate the artifacts needed to connect to the web service. 2. Implement and compile the client application. 3. Run the client. javax.xml.ws Service {abstract «use» StockQuoter Service «create» StockQuoter Client «use» «interface» StockQuoter NotFoundException 01/29/08 JAX-WS 11

12 Developing a Web Service Client The Client Implementation The client creates a Service object, obtains a stub from it, and then simply invokes its methods. public class StockQuoterClient { public static void main(string[] args) throws Exception { StockQuoterService service = new StockQuoterService(); StockQuoter port = service.getstockquoterport(); double quote = port.getquote( IBM );... 01/29/08 JAX-WS 12

13 Web Service Client Using Alternate Address You can tell the client to use an alternate address You may use this feature to introduce a monitor for the traffic You may us Tcpmon ( public class StockQuoterClient { public static void main(string[] args) throws Exception { StockQuoterService service = new StockQuoterService(); StockQuoter port = service.getstockquoterport(); BindingProvider bp = (BindingProvider) port; bp.getrequestcontext().put(bindingprovider.endpoint_address_property, " double quote = port.getquote( IBM );... 01/29/08 JAX-WS 13

Programming Web Services in Java

Programming Web Services in Java Description Audience This course teaches students how to program Web Services in Java, including using SOAP, WSDL and UDDI. Developers and other people interested in learning