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April 05 Prof. Ismael H. F. Santos - 1 Modulo II WebServices Prof. Ismael H F Santos.

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Presentation on theme: "April 05 Prof. Ismael H. F. Santos - 1 Modulo II WebServices Prof. Ismael H F Santos."— Presentation transcript:

1 April 05 Prof. Ismael H. F. Santos - 1 Modulo II WebServices Prof. Ismael H F Santos

2 April 05 Prof. Ismael H. F. Santos - 2 Bibliografia

3 April 05 Prof. Ismael H. F. Santos - 3 Ementa WebServices em Java

4 April 05 Prof. Ismael H. F. Santos - 4 WebServices Java SOA

5 April 05 Prof. Ismael H. F. Santos - 5 WebServices com Java A plataforma J2EE oferece as seguintes APIs: Document-oriented Java API for XML Processing (JAXP) processes XML documents using various parsers Java Architecture for XML Binding (JAXB) processes XML documents using schema-derived JavaBeans component classes Procedure-oriented Java API for XML-based RPC (JAX-RPC) sends SOAP method calls to remote parties over the Internet and receives the results Java API for XML Messaging (JAXM) sends SOAP messages over the Internet in a standard way Java API for XML Registries (JAXR) provides a standard way toaccess business registries and share information

6 April 05 Prof. Ismael H. F. Santos - 6 WebServices com Java A tecnologia Java oferece tambem as seguintes ferramentas: Java Web Services Developer Pack (Java WSDP) SOAP with Attachments API for Java (SAAJ) Com estas APIs você não precisa saber como criar o SOAP. Você só precisa saber utilizar as classes da API para criar e acessar os Web Services.

7 April 05 Prof. Ismael H. F. Santos - 7 URI HTMLHTTP UDDI WSDLSOAP State of the Art

8 April 05 Prof. Ismael H. F. Santos - 8 Web Service : How They Work? Components required Software which needs to be exposed as a Web service A SOAP Server (Apache Axis, SOAP::Lite, etc.) HTTP Server (if HTTP is used as the transport level protocol) SOAP Client (Apache Axis, SOAP::Lite etc.) (http transport) Requestor SOAP Messages Web Service Provider Endpoint SOAP Client

9 April 05 Prof. Ismael H. F. Santos - 9 Remote Web Service Repository (Web Sites) Write Client Code Service Requestor Invoke Web Service Manual Web Service Lookup SOAP Request SOAP Response WSDL - Web Service Description SOAP - Web Service Message Protocol WSDL File Remote Web service Publish Web Service HTTP GET Simple Web Service Invocation

10 April 05 Prof. Ismael H. F. Santos - 10 From S. Chandrasekaran’s Talk Web Service Description Why describe Web services? A service requestor needs to analyze a service for his requirements A Web service needs to provide the following information the operations it supports the transport and messaging protocols on which it supports those operations the network endpoint of the Web service Languages such as WSDL, DAML-S, RDF can be used for describing Web services WSDL – describes the syntactic information of a service DAML-S and RDF – describe the syntactic as well as the semantic information

11 April 05 Prof. Ismael H. F. Santos - 11 Web Service Description (WSDL) Abstract Description Concrete Description

12 April 05 Prof. Ismael H. F. Santos - 12 WebService Example SOA

13 April 05 Prof. Ismael H. F. Santos - 13 A Web Service example in Java SOAP-awareServlet (e.g. Apache Axis) SOAP-awareServlet Any class processing the incoming requests (“business logic” Any class processing the incoming requests (“business logic” Any class processing the incoming requests (“business logic” Any class processing the incoming requests (“business logic” Any class processing the incoming requests (“business logic” Any class processing the incoming requests (“business logic” Any class processing the incoming requests (“business logic” Any class processing the incoming requests (“business logic” HTTP Server Servlet engine (e.g. Apache Tomcat) Sending requests, getting results

14 April 05 Prof. Ismael H. F. Santos - 14 Usual principles of Java toolkits Writing server is easier than writing clients (but only regarding the toolkit, not the business logic) Servers may be written independently on the used toolkit Always test interoperability with a non-Java client (because of data serialization and de-serialization) Steps: write your service implementation make all your classes available to the toolkit deploy your service (usually done just once) restart the whole servlet engine test it with a client request

15 April 05 Prof. Ismael H. F. Santos - 15 Java SOAP Toolkits Apache SOAP (was IBM’s SOAP4J) Apache Axis (a follow-on to the Apache SOAP) …and many others

16 April 05 Prof. Ismael H. F. Santos - 16 package hello; public interface HelloWorld { String getHelloMessage(); void setHelloMessage (String newHello); } hello/HelloWorld.java package hello; public class HelloWorldService implements HelloWorld { String message = "Hello, world!"; public String getHelloMessage() { return message; } public void setHelloMessage (String newMessage) { message = newMessage; } hello/HelloWorldService.java

17 April 05 Prof. Ismael H. F. Santos - 17 import org.apache.axis.client.*; public class HelloWorldClient { public static void main (String [] args) { try { // prepare the call (the same for all called methods) Call call = (Call) new Service().createCall(); call.setTargetEndpointAddress (new java.net.URL( "http://localhost:8080/axis/services/Hello")); // call "get message" if (args.length == 0) { call.setOperationName ("getHelloMessage"); String result = (String)call.invoke( new Object[]{} ); System.out.println (result); System.exit (0); } HelloWorldClient.java

18 April 05 Prof. Ismael H. F. Santos - 18 // call "set message" and afterwards "get message" call.setMaintainSession (true); // TRY also without // this line... call.setOperationName ("setHelloMessage"); call.invoke ( new Object [] { args[0] } ); call.setOperationName ("getHelloMessage"); System.out.println (call.invoke ( new Object [] {} )); } catch (Exception e) { System.err.println ("ERROR:\n" + e.toString()); } HelloWorldClient.java

19 April 05 Prof. Ismael H. F. Santos - 19 Generated for HelloWorld HelloWorldServiceLocator implements HelloWorldService getHello() 1. Make an instance of this 3. Call methods on this proxy object HelloSoapBindingStub implements HelloWorld 2. Use it to make an instance of this

20 April 05 Prof. Ismael H. F. Santos - 20 public class HelloWorldClientFromStubs { public static void main (String [] args) { try { // prepare the calls (the same for all called methods) hello.generated.HelloWorldService service = new hello.generated.HelloWorldServiceLocator(); hello.generated.HelloWorld myHelloProxy = service.getHello(); // call "get message" if (args.length == 0) { String result = myHelloProxy.getHelloMessage() System.out.println (result); System.exit (0); } // call "set message" and afterwards "get message” myHelloProxy.setHelloMessage (args[0]); System.out.println (myHelloProxy.getHelloMessage()); } catch (Exception e) { System.err.println ("ERROR:\n" + e.toString()); } HelloWorldClientFromStubs.java

21 April 05 Prof. Ismael H. F. Santos - 21 Java XML Data Mapping How Java objects are converted to/from XML data (in order to be able to be put into SOAP messages) Important especially for the non-basic data types It’s easier if your non-basic data types are Java Beans (having set / get methods for members)

22 April 05 Prof. Ismael H. F. Santos - 22 Examples (Java Client) URL endpointURL = new URL(endpoint); Call call = new Call(); call.setSOAPTransport(m_httpconn); call.setTargetObjectURI("MessageService"); call.setMethodName("setMessage"); call.setEncodingStyleURI(Constants.NS_URI_SOAP_ENC);

23 April 05 Prof. Ismael H. F. Santos - 23 Examples (Java Client) Vector params = new Vector(); params.addElement( new Parameter("name", java.lang.String.class, name, null)); params.addElement( new Parameter("colour", java.lang.String.class, colour, null)); call.setParams(params); Response response = call.invoke(endpointURL, "");

24 April 05 Prof. Ismael H. F. Santos - 24 A Web Service example in Perl This is a module implementing the “business logic” package HelloPerl; use strict; use vars qw( $Message ); $Message = 'Hello, here is Perl.'; sub getHelloMessage { $Message; } sub setHelloMessage { $Message = shift; } 1; This is a cgi-bin script #!/usr/bin/perl -w -- Perl – use SOAP::Transport::HTTP; SOAP::Transport::HTTP::CGI -> dispatch_to('HelloPerl') -> handle; #!/usr/bin/perl –w use SOAP::Lite on_fault => sub {…}; print SOAP::Lite -> uri ('HelloPerl') -> proxy ('http://localhost/cgi-bin/helloserver.cgi') -> getHelloMessage -> result; This is a client

25 April 05 Prof. Ismael H. F. Santos - 25 SOAP::Lite a collection of (many) modules but they are loaded automatically when needed supports SOAP 1.1 specification all methods can be used for both setting and retrieving values: if you provide no parameters, you will get current value, and if parameters are provided, a new value will be assigned to the object and the method in question will return the current object (if not stated otherwise) which is is suitable for stacking these calls like: $lite = SOAP::Lite -> uri(’openBQS') -> proxy('http://industry.ebi.ac.uk/soap/openBQS');

26 April 05 Prof. Ismael H. F. Santos - 26 Using “wsdl” - directly #!/usr/bin/perl -w use SOAP::Lite on_fault => sub {…}; print SOAP::Lite -> service ('file:/home/senger/ws-ws/perl/Hello.wsdl') -> setHelloMessage (123); getting “.wsdl” file by using its URL then, you do not need to worry about autotyping #!/usr/bin/perl -w use SOAP::Lite on_fault => sub {…}; my $service = SOAP::Lite -> service ('file:./Hello.wsdl'); $service->setHelloMessage ($ARGV[0] or "Hello!!!"); print $service->getHelloMessage, "\n";


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