Transcript Intro to Programming Java Web Services using the JavaTM API for

Intro to Programming Java Web
Services using the JavaTM API for
XMLWeb Services (JAX-WS)
Bill Champlin
UCCS / CS526
Spring ‘09
Agenda
• Project Description / Purpose
• Overview of JAX-WS and Java Web
Services
• Programming Steps
• Advantages / Disadvantages
• References
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Project Description
• The Purpose of this Project is to Learn:
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Capabilities of the JAX-WS API
Steps to Programming a Service and a Client
SOAP XML Messaging
Role of JAX-WS in Java Web Services
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JAX-WS Overview
• Used to Build Java Web Services / Clients
• Uses SOAP Messages (also REST Msg Protocol)
– Over HTTP (also SMTP)
• Abstracts SOAP Messages from Developer
– Doesn’t Have to Write Code to Parse Messages
• NOT ALWAYS TRUE
– JAX-B Converts Java types to / from SOAP Messages
• Supports RPC or Document Messaging Styles
– RPC - Simple Types i.e. xsd:long, xsd: byte, etc
– Document - Complex Types by Creating new XML Schemas
• Supports Asynchronous Requests via Thread Pools
• Faults can be Thrown back to Clients
• Can Insert Binary Data as the Payload or as a SOAP
Attachment
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Java Web Services
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Basic Programming Steps [2]
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Code & Compile Annotated Java Web Service:
- Service Endpoint Interface (SEI) (Optional)
- Service Implementation Bean (SIB) Class
Run “wsgen” to Create “Artifacts”
- Java Types for Marshaling to / from XML Types
Deploy the Services using Endpoint. publish() (or High
Level Tools i.e. Metro, Glass Fish, etc.)
--> Creates the WSDL - Web Service Definition Language
Document (aka “Whiz-Dull”)
- XML file that Defines the Contract between SEI
and Clients
- WSDL can be found at: http://127.0.0.1:8888/teams?wsdl
4. Run “wsimport” to Create a Proxy SEI using WSDL
5. Code Client Against Proxy SEI
6. Execute Client
(Optional – Create Service Side or Client Side Message
Handlers)
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Data Flow
CLIENT
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SERVICE
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JAX-WS Sample Service [1]
// Service
@WebService
public class Teams {
private TeamsUtility utils;
public Teams() {
utils = new TeamsUtility();
utils.make_test_teams();}
@WebMethod
public Team getTeam(String name) {
return utils.getTeam(name); }
@WebMethod
public List<Team> getTeams() {
return utils.getTeams(); }}
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JAX-WS Sample Client [1]
// Client
class TeamClient {
public static void main(String[ ] args) {
TeamsService service = new TeamsService();
Teams port = service.getTeamsPort();
List<Team> teams = port.getTeams();
for (Team team : teams) {
System.out.println("Team: " + team.getName() +
" (roster count: " + team.getRosterCount() +")");
for (Player player : team.getPlayers())
System.out.println(" Player: " +
player.getNickname());
Advantages / Disadvantages
• Advantages:
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Easy to Create Simple Interoperable Services
Protocol Hidden from Developer (but Available)
Java Threading allows Asynchronous Services
Faults (exceptions) can be Propagated Back to
Client
• Disadvantages:
– Rapidly Changing s/w Versions / Tools
– Complex to Modify SOAP messages using API
– Binary Attachments Require Modifying WSDL
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References
Project Website:
http://cs.uccs.edu/~wchampli/cs526/project.html
Resources:
1.
Java Web Services: Up and Running, by Martin Kalin. Copyright 2009 Martin Kalin,
978-0-596-52112-7
2.
Sun Microsystems. The Java Web Services Tutorial for Java Web Services Developer’s
Pack, v2.0 February 17, http://java.sun.com/webservices/tutorial.html
3.
Core Java Volume 2, Advanced Features, Cay S. Horstmann and Gary Cornell, Sun
Microsystems Press, Prentice Hall, Copyright 2008, 978-0132354790, pgs 871-882.
4.
Create JAX-WS Service in 5 Minutes (Tutorial), Alexander Ananiev & MyArch,
http://myarch.com/create-jax-ws-service-in-5-minutes, Copyright © 2002-2006
5.
JAX-WS Tutorial http://www.javacoda.com/blog/?p=22
6.
stackoverflow Q&A site. http://stackoverflow.com/questions/100993/rmi-vs-webservices-whats-best-for-java2java-remoting
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