Tutorial on Web Services HY559 Infrastructure Technologies for Large- Scale Service-Oriented Systems Jason Polakis
[email protected] Required Software •Eclipse IDE for Java developers EE http://www.eclipse.org/downloads/ •Netbeans IDE http://netbeans.org/downloads/ •Apache Tomcat http://tomcat.apache.org/ •Apache AXIS2 http://axis.apache.org/axis2/java/core/download.cgi •Apache JUDDI http://juddi.apache.org/releases.html Getting Software • Either directly from given links, or: • In Ubuntu (as root) • To search for software – apt -cache search <program name> – Returns list of <packages> with short description • To install software – apt-get install <package> – Installs software, as well as dependencies Web Services “Any piece of software that makes itself available over the Internet and uses a standardized XML messaging system” •Extremely available •Language and platform independent •Distributed application components •Discoverable via a simple find mechanism •Components of Web Services – SOAP (Simple Object Access Protocol) – WSDL (Web Services Description Language) – UDDI (Universal Description, Discovery and Integration) Web Service Architecture •Web Service Protocol Stack –Service transport (transport messages between applications) •HTTP, SMTP, FTP –XML messaging (encode messages in common XML format ) • XML-RPC, WS-Addressing, and SOAP –Service description (describe public interface of service) –Service discovery (centralize services into common registry) •Programming models: –REST-based web services –SOAP-based web services SOAP-based Services •Use SOAP –protocol for exchanging structured information •Use WSDL –xml-based language for describing Web services •WSDL file –created based on the JAVA code in the service –exposed on the net •To use service, must create a client –based on WSDL info •Messages exchanged in SOAP •Java API for XML Web Services (JAX-WS) model also used for SOAP services.