© 2006 by ibm; made available under the epl v1.0 | cambridge | september 8, 2006 501 developing...

© 2006 by IBM; made available under the EPL v1.0 | Cambridge | September 8, 2006

501 Developing Java Web Services with WTP

Arthur RymanIBM Rational Software

2 © 2006 by IBM; made available under the EPL v1.0 | Cambridge | September 8, 2006

Abstract

The Eclipse Web Tools Platform (WTP) project provides a set of tools for developing standards-based multi-tier JavaTM Web applications. This session focuses on the tools available for developing Web services in WTP 1.5. These tools will be illustrated through a series of scenarios which include top-down Web service creation from XSD and WSDL, bottom-up Web service creation from Java classes, generating Java client proxies from WSDL, using JAX-RPC in Web applications, testing Web services for WS-I compliance, and publishing Web services using UDDI and WSIL. This is an intermediate level session aimed at developers and managers who are creating and using Java Web services. Some prior experience with WTP is helpful. After this session you will have a good understanding of how WTP can be used to develop Java Web services.


About this talk

You will use WTP to develop Web services in a sequence of iterations

The example used is League Planet, a fictitious Web site for amateur sports leagues

For more information, see Chapter 10 of the forthcoming book, “Java Web Application Development Using Eclipse”

For the most benefit, you should follow along You are expected to be comfortable using Eclipse and

programming in Java Some prior knowledge of Web services would be useful


Code Examples

This tutorial is based on a complete working Web application called League Planet

All source code is provided in the examples directory The directory structure is: <topic>/<iteration>/<project> e.g. webservices/iteration1/IceHockeyService/schedule.xml To make the application work, you must create some projects

and generate some code


Introduction

Web services have emerged as the standard technology for integrating heterogeneous systems across the Internet and intranet

e.g. services implemented on J2EETM application servers and clients implemented on .NET desktops or PHP Web servers

The key technologies are: Extensible Markup Language: XML – for messages

XML Schema Description: XSD – for message description

Web Service Description Language: WSDL – for service description

Universal Description, Discovery, and Integration: UDDI – for service registries

Web Service Interoperability: WS-I – for interoperability


Overview of Iterations

1. Developing Web Services Top-Down2. Developing Web Services Bottom-Up3. Generating Web Service Client Proxies4. Testing Web Services for Interoperability5. Using Web Services in Web Applications6. Discovering and Publishing Web Services


Iteration 1 –Developing Web Services Top-Down


Iteration 1 - Developing Web Services Top-Down

Top-Down development means designing the Web service interface first and then developing the implementation code

This approach yields the best interoperability because the underlying implementation details do not “bleed through” into the interface

This approach is required if the messages use existing industry or corporate XML document formats

You need to learn XSD and WSDL design skills Luckily, WTP has two great editors that make this task easier


Iteration 1 Overview

1. Use the XSD editor to describe the League Planet schedule format

2. Use the WSDL editor to describe a Web service for querying schedules

3. Use the Web service wizard to generate a Java skeleton for the service and deploy it to the Axis SOAP engine running on Tomcat

4. Fill in the implementation of the skeleton by accessing the League Planet business tier

5. Use the Web service explorer to test the Web service


Create a new Dynamic Web Project named IceHockeyService to contain the Web service.


Describing schedule.xml

League Planet has an XML format for schedules Import IceHockeyService/schedule.xml for an example instance

document Your goal is to describe this format using XSD


Create a new XML Schema file named schedule.xsd in IceHockeyService.


schedule.xsd

In general, there are many equivalent ways to describe a given format using XSD

For Web services, it’s a good practice to describe formats in a way that works well with XML data binding toolkits such as JAX-RPC

Define complexTypes for the content model of each element The XSD editor lets you edit in the source tab, the graphical tab,

the outline view, and the property view Try creating schedule.xsd Import IceHockeyService/schedule.xsd before proceeding


View schedule.xsd in the Graph tab of the XSD editor.


View ScheduleContent of schedule.xsd in the Graph tab of the XSD editor.


View schedule.xsd in the Outline view of XSD editor.


query.wsdl

Now that you’ve described the message format using XSD, you next goal is to describe a Web service for retrieving it

For simplicity, the Web service will have a single operation named getSchedule

The operation will take as input, the schedule id, and return as output the corresponding schedule document


Create a new WSDL file named query.wsdl in IceHockeyService.


Enter the namespace for the WSDL and have the wizard generate a skeleton document for you using the SOAP binding and document/literal style.


WSDL editor

You can edit the document in the graph tab, the source tab, the outline view, and the property view.

WSDL describes Web service using a hierarchy of constructs: message, portType, binding, and service

The editor has a wizard that generates binding content for you Try creating query.wsdl Import IceHockeyService/query.wsdl before proceeding


View query.wsdl in the Graph tab of the WSDL editor.


View query.wsdl in the Outline view of the WSDL editor.


Deploying query.wsdl

You have now described the Web service Your next goal is to deploy it This step assumes you have previously installed Tomcat and

added it to WTP Select query.wsdl and execute the command Web Services >

Generate Java bean skeleton This command launches the Web service wizard


Check the boxes to Install and Start the Web service and click Next.


The wizard validates your WSDL. Click Next.


The wizard selects Axis and Tomcat. Click Next.


The wizard lets you select a source folder and change the package name for the generated skeleton. Accept the defaults and click Next.


Click Start server, wait, then click Next.


The wizard lets you publish the WSDL to UDDI. Just click Finish.


What the wizard did.

Installed the Axis SOAP engine in your project Generated the Java bean skeleton for you service and lots of

Java XML data binding classes in the src folder Copied query.wsdl to WebContent/wsdl/querySOAP.wsdl and

set its endpoint to your Web application (also copied schedule.xsd)

Created the Axis deployment descriptor WebContent/WEB-INF/server-config.wsdd

Created a couple of handy Axis files to deploy and undeploy your Web service in a subfolder of WebContent/WEB-INF

Started Tomcat to make your Web service available


The IceHockeyService project after the wizard completed. Select AxisServlet and execute the command Run As > Run on Server.


View the list of deployed Web services.


LeaguePlanetModel Business Tier

The Web service is running but it just returns null at this point You next need to fill in the implementation of the Java bean

skeleton The Web service needs to access the League Planet business

tier If you have not previously done so, create a new J2EE Utility

Project named LeaguePlanetModel and import the source code from LeaguePlanetModel/src into it


Select IceHockeyService and open its Properties dialog. Add LeaguePlanetModel as a J2EE Module Dependency.


View the module structure of the server in the Servers view.


Filling in the Java bean skeleton

You now have a Web service skeleton and access to the League Planet business tier.

Your next goal is to implement the Web service. The generated skeleton class is

com.leagueplanet.ws.query.QuerySOAPImpl Import

IceHockeyService/src/com/leagueplanet/ws/query/QuerySOAPImpl.java now

This modified skeleton simply delegates to a new class com.leagueplanet.Query to avoid confusion with the generated code

Create this new class now and try to implement it Import IceHockeyService/src/com/leagueplanet/Query.java before

proceeding


Testing the Web service

At this point the Web service is ready to test You will test it using the Web Service Explorer Select IceHockeyService/WebContent/wsdl/querySOAP.wsdl

and execute the command Web Services > Test with Web Service Explorer

The Web Service Explorer will start and open a new Web browser in the editor area


View querySOAP.wsdl in the Web Service Explorer. Click the getSchedule link.


View the getSchedule operation. Enter 1 in the scheduleId field and click Go. The schedule is returned in the Status pane.


Double-click the Status pane to maximize it. Click the Source link to view the SOAP message.


View the SOAP message source. Click the Form link to return to the Form display.


Iteration 2 –Developing Web Services Bottom-Up


Iteration 2 – Developing Web Services Bottom-Up

Bottom-Up development starts with a Java service class and generates the WSDL from it

This approach is more productive for Java developers since XSD and WSDL design skills are not required

It is suitable when the Java class uses simple data transfer objects as inputs and outputs of its operations

It is dangerous because the resulting XSD may be complex and less interoperable

There is risk of implementation “bleed through” into the service interface and coupling between the client and service



1. Develop a Java service class to get details about a game and to update its score

2. Use the Web service wizard to deploy the service3. Use the WSDL editor to view the generated WSDL


Create the Java service implementation

The service implementation will be created in the package com.leagueplanet

Import the following Java classes into IceHockeyService/src/com/leagueplanet:

GameDetail.java – the data transfer class

GameException.java

ScoreException.java

Update.java – the service class The service has two operations:

getGame

updateScore The service accesses the League Planet business tier


Deploy the service

Select Update.java and execute the command Web Services > Create Web service


Check the Install and Start Web service boxes. You could click Finish at this point since the wizard picks sensible defaults. Click Next to step this the pages.


The wizard lets you select a different class. Click Next.


The wizard lets you select a different project. Click Next.


The wizard lets you select the methods to include as operations and the style to use. Click Next.


Confirm that Update was deployed using the AxisServlet.


View the generated Update.wsdl in the WSDL editor.


Iteration 3 –Generating Web Service Client Proxies


Iteration 3 – Generating Web Service Client Proxies

Web services can be invoked from programs written in many programming languages, e.g. Java, C#, PHP, JavaScriptTM etc.

Most languages support dynamic invocation and do not require any code generation

A client proxy simplifies Web service invocation by producing a class that resembles the service interface

In J2EE, client proxies are specified by JAX-RPC and its follow-on JAX-WS



1. Use the Web service wizard to generate a Java client proxy and a JSP test client

2. Test the service using the JSP test client


Select Update.wsdl and execute the command Web Services > Generate Client. The wizard opens. Check the Install, Test, and Monitor boxes and click Next.


The wizard validates the WSDL. Click Next.


The wizard lets you select a different client project. Click Next.


The wizard lets you change the package for the generated client proxy code. Click Next.


The wizard lets you select the operations to include in the generated JSP test client. It also lets you select a different output folder for the JSPs. Click Finish.


What the wizard did

Created a new Dynamic Web project named IceHockeyServiceClient

Installed Axis in IceHockeyServiceClient Generated Java proxy code including XML data binding classes

and exceptions in IceHockeyServiceClient/src/com/leagueplanet Generated JSP test client code in

IceHockeyWebContent/sampleUpdateProxy Started an instance of the TCP/IP Monitor and configured the

JSP client to use it Opened the JSP test client in a Web browser You are now ready to test the Web service


Click the getGameDetail method. Enter gameId = 1 and click Invoke. View the game details in the Result pane.


Click the updateScore method. Enter input parameters and click Invoke. The operation returns an empty result.


Click the getGameDetails method. Enter gameId =1 and click Invoke. View the updated score in the Result pane to confirm that the updateScore operation works correctly.


Iteration 4 –Testing Web Services for Interoperability


Iteration 4 – Testing Web Services for Interoperability

The main value proposition of Web services is interoperability between heterogeneous systems, e.g. .NET, PHP, JavaScript

WS-I.org was established to define interoperability profiles WTP lets you validate both your WSDL and your Web service

implementations for interoperability


Click the getEndpoint method. Click Invoke. View the endpoint address in the Result pane. Note the port number.


Open the Preferences dialog and select the TCP/IP Monitor page. Note the port number of the monitor matches the endpoint.


View the recorded messages in the TCP/IP Monitor view. Click the Validate icon (document with checkmark).


The wizard lets you select a folder to store the message log file. Select IceHockeyServiceClient and click Next.


The wizard lets you validate the message against a WSDL file. Select Update.wsdl and click Next.


The wizard lets you select the WSDL element to use. Select the Update port and click Finish.


The messages are valid. In the event of errors, markers are placed in the generated log file.


Use the Profile Compliance and Validation Preference page to control the level of validation.


Iteration 5 –Using Web Services in Applications


Iteration 5 – Using Web Services in Applications

Web services can be used in applications developed with many programming languages and technologies

Web services allow alternate user interfaces to be developed Web services allow decoupling of the presentation and business

tiers within an enterprise Java applications can use JAX-RPC or JAX-WS to access both

Java and non-Java Web services



1. Develop a user interface in IceHockeyServiceClient based on JSPs and servlets

2. Access the Update Web service from the servlet using the Java client proxy


Create a new servlet in IceHockeyServiceWeb. Enter package and class names. Click Next.


Enter a description and URL mapping. Click Next.


Check the doGet and doPost boxes. Click Finish.


Develop the user interface

The wizard created and configured the UpdateScoreServlet Create two new JSPs:

score-form.jsp – to input score, has Submit button

score-confirmation.jsp – to confirm score update, has Edit button Code the servlet as follows:

doGet takes a gameId query parameter, calls the service to get the game detail, puts the game detail in the session, and forwards to score-form.jsp

doPost takes gameId, visitorScore, and homeScore query parameters, calls the service to update the score, gets the new game detail, and forwards to score-confirmation.jsp


Import the UI code

Just kidding! That was way too much code to write. Import the following code into IceHockeyService:

/src/com/leagueplanet/ui/UpdateScoreServlet.java

/WebContent/score-form.js

/WebContent/score-confirmation.js

/WebContent/schedule.css

/WebContent/validator.css

/WebContent/score-validator.js Note the JAX-RPC usage pattern in the servlet


Select the updateScore servlet and execute the command Run As > Run on Server. A GameException is thrown because you didn’t provide a gameId query parameter.


Append ?gameId=1 to the URL and try again. Now the score form is displayed. Enter a new score and click Submit.


The score confirmation page is displayed. Click Edit to update the score again.


Iteration 6 –Discovering and Publishing Web Services


Iteration 6 – Discovering and Publishing Web Services

You can look for available Web services in UDDI registries You can also publish Web services in UDDI registries UDDI provides a SOAP Web service for dynamic discovery You can also look for and publish Web services using the

simpler WSIL document format In the future, Web crawlers might harvest WSIL documents and

automatically populate UDDI registries so you can take advantage of the powerful UDDI inquiry support



1. Explore a UDDI registry2. Explore a WSIL document3. Create a WSIL document


Launch the Web Service Explorer. Select the XMethods UDDI Registry and click Go.


View the registry details. Click the Find link.


Enter a name for the query. Search for Services. Enter a partial service name to search for and click Go.


View the query results. Click the service links to explore the services.


View the webservicex.com service. Click the Add to WSDL Page icon (with plus sign).


View the WSDL details. Click the StockQuoteSOAP link.


View the WSDL binding details. Click the GetQuote link.


View the operation details. Click the Add link and enter a stock symbol. Click Go.


View the result of the operation in the Status pane.


WSIL

As you can see from this exercise, UDDI is very complex WSIL is a simpler way to publish information about Web services WSIL can refer to WSDL, UDDI, and other WSIL documents WSIL was jointly developed by IBM and Microsoft Microsoft still uses the precursor, DISCO There is not a lot of WSIL deployed XMethods support it and several other technologies


Surf to http://www.xmethods.net. Click the Access link.


View the many access methods supported by XMethods. Copy the WS-Inspection link.


Open the WSIL page of the Web Service Explorer (page with globe icon). Paste in the XMethods WSIL URL, select WSDL Services, and click Go.


View the list of WSDL services registered at XMethods.


Create an new inspection.wsil file in IceHockeyService/WebContent


Edit inspection.wsil

Select IceHockeyService/WebContent/wsdl/querySOAP.wsdl and execute the command Web Services > Generate WSIL to create querySOAP.wsil

Repeat for Update.wsdl Merge the contents of these into inspection.wsil and add

abstracts Import IceHockeyService/WebContent/inspection.wsil before

proceeding


Enter http://localhost:8080/IceHockeyService/inspection.wsil in WSIL page, select WSDL Services and click Go.


View the available WSDL services. Click the QuerySOAP.wsdl link.


View the QuerySOAP.wsdl details.


Web Services Summary

In this tutorial you have covered all the major functional areas of Web service development that are available in WTP

Tools covered included the Web Service Wizard, Web Service Explorer, XSD Editor, WSDL Editor, TCP/IP Monitor, and WS-I Test Tools

Technologies covered include XSD, WSDL, SOAP, UDDI, WSIL, JAX-RPC, and Axis

For further details consult the WTP Help and Web site


EclipseWorld 2006WTP Track and Subprojects


The JSF Tools Project Technology Preview release with WTP 1.5

Features Full-fledged Faces Config Editor Enhanced JSF-JSP Source Editor JSF Library Registry Extensible framework

Download http://download.eclipse.org/webtools/downloads/drops/R1.5/R-1.5.0-2006062814

55/ Release 1.0-WTP2.0

Features Visual JSF Page Designer JSF 1.2 support First release of API’s

Requirements http://wiki.eclipse.org/index.php/Release_1.0_Requirements


AJAX Toolkit Framework

Provides tools for developing AJAX/DHTML applications JavaScript Debugger

Embedded Mozilla Browser

DOM Inspector / JavaScript Console

JavaScript Validation Extensible framework for adding AJAX runtimes to eclipse

AJAX Personality Builder New Enhancements

New CSS Tools and Improved DOM Inspector

Configuring and Deploying to a HTTP Server

JavaScript Debugging Enhancements Debugging using a HTTP/File URL. Expression Support

Project in Incubation Phase (www.eclipse.org/atf).


Dali JPA Tools Project

Tools and frameworks for building applications with the Java Persistence API (JPA) —part of Java EE 5. Support for both EE and SE

development

O-R Mapping validation with intelligent code assist for both Java and Database values.

Quick start generation wizards

Entities from Tables Tables from Entities

Salvador Dalí. The Persistence of Memory. 1931. © 2005 Salvador Dalí, Gala-Salvador Dalí Foundation/Artists Rights Society (ARS), New York


WTP Track

Wednesday, September 6 All Day T-4 Develop Better J2EE Applications With the Web Tools Platform – Judd

Thursday, September 7 8:30 AM 101 Quick Tour of the Eclipse Web Tools Platform – Ryman 8:30 AM 107 Leveraging JSF Components – Katz 10:30 AM 201 How to Build Java Web Applications With the Web Tools Platform –

Ryman 1:15 PM 301 Facing JavaServer Faces Development With JSF Tools – Jacobi 3:15 PM 401 Consuming and Producing Web Services With Web Tools – Judd

Friday, September 8 8:45 AM 501 Developing Java Web Services With the Web Tools Platform – Ryman 10:45 AM 601 Extending the Web Tools Platform With Ant and PDE – Shittu 1:45 PM701 Building Applications With the Java Persistence API and Dali – S.

Smith 3:45 PM 801 How to Use and Extend Eclipse’s XML and Schema Tools – Williams,

Salter, Dahyabhai


Attributions

Java and all Java-based trademarks are trademarks of SunMicrosystems, Inc. in the United States, other countries, or both.

Other company, product, or service names may be trademarks or service marks of others.

© 2006 by ibm; made available under the epl v1.0 | cambridge | september 8, 2006 501 developing...

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