Building a Simple Web Service – A Tutorial

 ·         By Jeevaraj Gnanaselvan Dhanaraj (jeevaraj_1970@yahoo.com)

      (Jeeva has over 7 years of experience in designing and developing enterprise class web applications using JAVA and J2EE technologies.

      He currently works for Itreya Technologies, Bangalore, leading a team of over 10 programmers and designers, developing a multi-user, distributed, web-based workflow application)

 ·        Introduction

In this tutorial we will create a simple web service and a client web application using eclipse IDE along with Lomboz plug in. We will also deploy and test the web service on Tomcat 5.5.4 web application server. This application, while simple, provides a good introduction to Web service development and some of the Web development tools available.

 ·         Environment

J2SDK 1.4.2
http://java.sun.com/

Eclipse 3.1

http://www.eclipse.org/

Tomcat 5.5.4

http://tomcat.apache.org/

Lomboz 3.1RC2
http://lomboz.objectweb.org/

·         Installation

Install JDK (in D:\j2sdk1.4.2_04)

Install Tomcat (in E:\Tomcat5.5)

Install Eclipse (in E:\Eclipse3.1)

Install Lomboz (in E:\Eclipse3.1)

·         Setting up

1. Set up the installed JRE in eclipse (Windows -> Preferences -> Java -> Installed JREs)

2. Set up the installed runtime for server in eclipse (Windows -> Preferences -> Server -> Installed Runtimes)

3. Set up the Server view in eclipse (Windows -> Show View -> Other)

4. Set up the Tomcat Server by right clicking and selecting New -> Server option from the Server view in eclipse

·         Creating a Web service

1. Create a new Dynamic Web Project in eclipse (File -> New -> Other)

2. Enter name as “WebServiceTutorial”, select project location as “E:\Test” and select Apache Tomcat v5.5 as the Target server.

3. Now create a new Java class from the Project Explorer (Dynamic Web Projects -> Java Source -> New -> Class)

4. Enter name as “Hello” and package as “com.tutorial”.

5. Add a simple method in the “Hello” class as below.

            public String sayHello(String name){

                        return "Hello " + name;

            }            

6. Save and build the project.
7. Create a new Web service in eclipse (File -> New -> Other)

8. Select Generate a proxy.
9. Select Test the Web service.
10. Select Overwrite files without warning.

11. Select or enter the Bean name as “com.tutorial.Hello”. This is the java class that we just now created.

12. Continue the wizard by clicking Next and finish.
13. On Finish, the Tomcat server starts up and launches the Test client.
14. Verify the generated contents. Look for Hello.class and the generated JSPs as below.

15. Verify the Tomcat folder and ensure the newly created web applications – WebServiceTutorial, WebServiceTutorialClient.

16. We can also run the following url from the browser to access/test the Web service.

http://localhost:8080/WebServiceTutorialClient/sampleHelloProxy/TestClient.jsp

17. If servlet error “org.eclipse.jst.ws.util.JspUtils cannot be resolved or is not a type” is thrown on the browser, then copy the webserviceutils.jar file from the E:\Eclipse3.1\eclipse\plugins\org.eclipse.jst.ws.consumption_0.7.0 into the WEB-INF\lib folder of the WebServiceTutorialClient application and restart the Tomcat server.

18. The browser displays the methods available in the web service.

19. Click on the sayHello(..) method, enter your name (for e.g. “Jeeva”) in the inputs section and click “Invoke”.

20. The browser greets using the web service.

21. The WSDL for the Hello Web service can be found in E:\Test\WebServiceTutorial\WebContent\wsdl\Hello.wsdl. On double-click, the WSDL opens in a graphical editor.

22. Right-click on the WSDL file and explore the options to test the web service / publish the WSDL file / generate client / etc.

·         Conclusion

In this tutorial we learned how to create a simple web service and a client web application using eclipse IDE along with Lomboz plug in. We also deployed and tested the web service on Tomcat 5.5.4 web application server. This application, while simple, provides a good introduction to Web service development and some of the Web development tools available.