1. Web Services with JAX-RPC and Apache Axis
Tuesday, September 18, 2018
Web Services with JAX-RPC and Apache Axis
Sep. 18, 2002
Pankaj Kumar
Software Architect,
Web Services Management Organization,
Hewlett Packard Co.

2. Session Objectives Web Services in Perspective
Tuesday, September 18, 2018
Session Objectives
Web Services in Perspective
Learn about Web Services, wire-level interoperability standards and portable Java APIs.
Get to know JAX-RPC and Apache Axis to consume and produce Web Services.
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3. Tuesday, September 18, 2018
Speaker Introduction
More than 12 years of development and project management experience
Worked on Web Services product development at HP
Expert Group Member of JAX-RPC and JSR109
Contributor to Apache Axis and Cocoon projects
Author of open source project XPB4J (
Frequent speaker at developer conferences
Authoring a book on J2EE and Web Services Security
Architect with HP Web Services Mgmt. Operation
Home Page:
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4. Outline of the Session Introduction to Web Services
Tuesday, September 18, 2018
Outline of the Session
Introduction to Web Services
Web Services Standards
Java support for Web Services
Apache Axis
Installing Apache Axis
Invoking a service
Deploying a service
Handlers
Serializers and Deserializers
Where to find more information
Bulk of the session is focussed on working with Apache Axis.
JAX-RPC is covered as part of discussion on Apache Axis.
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5. Web Services Infrastructure
Language and platform independent infrastructure for loosely-coupled, inter-operable, app2app communication over the Internet.
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6. Web Services (Contd.) Language and platform independent =>
separation of specification and implementation
Loosely coupled =>
message based, synchronous and asynchronous interactions.
Over the Internet =>
No centralized control, use of established protocols, security considerations.
Inter-operable =>
Standards based.
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7. Early (Internet) Technologies
SMTP/MIME
is still the killer app
FTP, NNTP
HTTP/HTTPS, HTML
the protocol behind Internet’s popularity
Most of these facilitated app to human interaction
over the Internet/intranet
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8. Early (intranet) Technologies
DCE from OSF -- RPC based, procedural
ORB -- object oriented, mostly synchronous
CORBA, COM/DCOM from Microsoft, Java RMI/EJBs
MOM -- message oriented, synchronous as well as asynchronous
JMS ( Java API standard )
Many proprietary implementations
Most of these facilitated app2app interaction within a
trusted intranet and without much consideration to
interoperability across different implementations.
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9. App2App Interaction -- the Web Services Way
Transport protocol
HTTP/HTTPS
Data Encoding
SOAP (Simple Object Access Protocol), XML Schema
Interface Description
WSDL (Web Services Description Language)
Service Description and Discovery
UDDI (Universal Description, Discovery and Integration)
Security
WS-Security, XML-Signature, XML-Encryption, ...
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10. The Web Services Way
Web Services standards (SOAP, WSDL, … ): based on widely accepted Internet friendly technologies (HTTP/HTTPS, XML, …), are mostly orthogonal to each other and enjoy broad support from vendors
Web Services: Network accessible programs, expose functionality by receiving/sending SOAP messages over HTTP/HTTPS, and describe this interface as WSDL descriptions.
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11. Additional Web Services Infrastructure Components
Key Management (Security)
XKMS
Web Services Management
OMI (Open Management Interface)
...
Interesting thing to note is that these
are Web Services in themselves
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12. SOAP In One Slide XML based protocol for exchange of information
SOAP1.1 Message
Structure
XML based protocol for exchange of information
Encoding rules for datatype instances
Convention for representing RPC invocations
Designed for loosely-coupled distributed computing
No remote references
Used with XML Schema
Transport independent
SOAP with Attachments allow arbitrary data to be packaged.
SOAP
Envelope
Header
Entries
[Header
Element]
Body
Element
[Fault
Element]
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13. WSDL in One Slide A WSDL document describes
Structure
A WSDL document describes
What the service can do
Where it resides
How to invoke it
WSDL are like IDL but lot more flexible and extensible
Defines binding for SOAP1.1, HTTP GET/POST and MIME
WSDL descriptions can be made available from an UDDI registry
WSDL
Document
[Types]
{Messages}
{Port Types}
{Bindings}
{Services}
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14. Java APIs for Web Services
SOAP messages as Java objects
SAAJ ( SOAP with Attachments API for Java)
Programming Model
JAX-RPC ( JSR101), JSR109, EJB2.1
Accessing WSDL descriptions
JWSDL (JSR110)
Accessing Web Services Registries
JAXR (Java API for XML Registries)
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15. SAAJ Object Model SOAPMessage SOAPPart AttachmentPart Node SOAPElement
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SAAJ Object Model
SOAPMessage
SOAPPart
AttachmentPart
Node
SOAPElement
SOAPBody
SOAPHeader
SOAPBodyElement
SOAPHeaderElement
SOAPEnvelope
SOAPFault
SOAPFaultElement *
There are some additional Factory classes to create the concrete objects.
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16. JAX-RPC WSDL/XML to Java Mapping Java to WSDL/XML Mapping
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JAX-RPC
WSDL/XML to Java Mapping
Java to WSDL/XML Mapping
SOAP Message with Attachments
Client API
Classes generated from WSDL
Dynamic Proxy
DII call Interface
SOAP Message Handler
Extensible Type Mapping
Java and WSDL/SOAP type systems are very different.
dotNet type system is much closer to WSDL/SOAP type system.
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17. JAX-RPC Physical Architecture
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JAX-RPC Physical Architecture
Transport
Protocol (SOAP)
Server Side JAX-RPC
Runtime System
JAX-RPC API
Client Side JAX-RPC
Stub
Service Endpoint
WSDL description
WSDL<->Java Mapping
Service Client
Dispatch
Container
There are some additional Factory classes to create the concrete objects.
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18. Interoperability and JAX-RPC
Tuesday, September 18, 2018
Interoperability and JAX-RPC
WSDL description
Vendor prod.
<Vendor B>
JAX-RPC impl.
<Vendor A>
J2EE Container
<Vendor D>
<Vendor C>
Client
Service
There are some additional Factory classes to create the concrete objects.
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19. Apache Axis A SOAP Processing Engine
JAX-RPC Client System
JAX-RPC Server System ( Servlet based )
SAAJ implementation
Flexible and extensible architecture
Tools, Examples, Documentation, …
A great place to learn about Web Services !!
Open-source, hosted by Apache Software Foundation
Ready for use ( RC1 released on Sep. 6)
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20. Install & Deploy Apache Axis
Make sure that you have
J2SE SDK 1.3 or 1.4: We will use 1.4
A Servlet Container: We will use Tomcat4.0.1
Download xml-axis-rc1-bin.zip from
Unzip it and look at the dir. tree. Note that Axis runs as a Servlet.
Deploy Axis.
Copy webapps\axis tree to webapps directory of Tomcat.
Alternatively, modify server.xml of Tomcat.
Run Tomcat: issue bin\startup from Tomcat home.
Direcotry Structure:
axis-1_0
webapps
lib
docs
samples
axis
WEB-INF
lib
classes
web.xml ……
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21. Test the Deployment Point your browser to http://localhost:8080/axis
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22. A Simple Example
AddFunction: A simple Java class with method to add two integers. Notice the filename extension – it is .jws ( for Java Web Service).
Deploy it. Just copy the AddFunction.jws file to webapps/axis directory.
Examine its WSDL description. Point your browser to
// File: AddFunction.jws
public class AddFunction {
int addInt(int a, int b){
return(a+b); }
Note: All sources with instructions
to run are available at my web-site:
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23. Writing the Client Program
There are many ways to write a Client program
Using Dynamic Invocation Interface ( DII)
Using generated Stubs from Service WSDL description
Using Dynamic Proxy
We will look at each of these
Writing the client requires more work
than writing the service
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24. AddFunctionClient – using DII
// File: lesson1\client\dii\AddFunctionClient.java, edited for presentation
import javax.xml.rpc.Call;
import javax.xml.rpc.Service;
import javax.xml.namespace.QName;
public class AddFunctionClient {
public static void main(String [] args) {
try {
String endpoint = "
Service service = new Service();
Call call = (Call) service.createCall();
call.setOperationName(new QName(endpoint, "addInt"));
call.setTargetEndpointAddress( new java.net.URL(endpoint) );
Integer ret = (Integer)call.invoke(new Object[]{new Integer(5), new Integer(6)});
System.out.println("addInt(5, 6) = " + ret);
} catch (Exception e) {
System.err.println("Execution failed. Exception: " + e); }
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25. Compiling and Running the DII Client
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26. AddFunctionClient – using Dynamic Proxy
// File: lesson1\client\dproxy\AddFunctionClient.java, edited for presentation
import javax.xml.namespace.QName;
import javax.xml.rpc.*;
public class AddFunctionClient {
public static void main(String [] args) {
try {
String wsdlUrl = "
String nameSpaceUri = "
String serviceName = "AddFunctionService";
String portName = "AddFunction";
ServiceFactory serviceFactory = ServiceFactory.newInstance();
Service afs = serviceFactory.createService(new java.net.URL(wsdlUrl),
new QName(nameSpaceUri, serviceName));
AddFunctionServiceIntf afsIntf = (AddFunctionServiceIntf)afs.getPort(
new QName(nameSpaceUri, portName), AddFunctionServiceIntf.class);
System.out.println("addInt(5, 3) = " + afsIntf.addInt(5, 3));
} catch (Exception e) {
System.err.println("Execution failed. Exception: " + e); }
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27. Compiling and Running the Dynamic Proxy Client
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28. AddFunctionClient – using Generated Stubs
Generate the stubs:
java org.apache.axis.wsdl.WSDL2Java \
// File: lesson1\client\stub\AddFunctionClient.java, edited for presentation
Import localhost.*;
public class AddFunctionClient{
public static void main(String [] args) {
try {
AddFunctionService afs = new AddFunctionServiceLocator();
AddFunction af = afs.getAddFunction();
System.out.println("addInt(5, 3) = " + af.addInt(5, 3));
} catch (Exception e) {
System.err.println("Execution failed. Exception: " + e); }
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29. Generating Stubs, Compiling and Running the Stub Client
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30. Deployment Descriptors
JWS deployment is simple, but has limitations:
You must have the source code
Can’t specify custom type mappings, handlers etc.
WSDD (Web Services Deployment Descriptors) allow more flexible deployments
Handlers in request or response path
Custom type mappings
Different transports – HTTP/S, TCP/IP, DIME
Different Dispatchers – Java Class, EJB, Servlet …
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31. Adding complexitiy to the Simple Example
AddFunction1: A simple Java class with method to add two Complex numbers. Complex is user defined Java class.
Deploy it.
Compile sources
Copy .class files.
Write deployment descriptor
Run AdminClient.
Examine its WSDL description. Point your browser to
// File: Complex.java
public class Complex {
public Complex(){}
public double getR(){ … }
public void setR(double r){ … } …
public Complex add(Complex c){ … }
// File: AddFunction1.java
public class AddFunction1 {
public Complex addComplex
(Complex a, Complex b){
return a.add(b); }
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32. The Deployment Descriptor
// File: lesson2\service\deploy.wsdd
<deployment xmlns="
xmlns:java="
<handler name="print" type="java:LogHandler"/>
<service name="AddFunction1Service" provider="java:RPC">
<requestFlow>
<handler type="print"/>
</requestFlow>
<parameter name="className" value="AddFunction1"/>
<parameter name="allowedMethods" value="*"/>
<beanMapping qname="myNS:Complex" xmlns:myNS="urn:BeanService"
languageSpecificType="java:Complex"/>
</service>
</deployment>
Note:
(1) xmlns:java
(2) A handler in the request path
(3) Dispatch to RPC provider
(4) Bean type mapping
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33. Deploying the Service
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34. AddFunction1Client – using Generated Stubs
Generate the stubs:
java org.apache.axis.wsdlWSDL2Java \
// File: lesson2\client\stub\AddFunction1Client.java, edited
import localhost.*;
import BeanService.*;
public class AddFunction1Client {
public static void main(String [] args) throws Exception {
Complex a = new Complex();
Complex b = new Complex();
a.setR(10.0); a.setI(5.0);
b.setR(3.0); b.setI(2.0);
AddFunction1Service afs = new AddFunction1ServiceLocator();
AddFunction1 af = afs.getAddFunction1Service();
Complex ret = af.addComplex(a, b);
System.out.println("addComplex(a + b) = ("
+ ret.getR() + ", " + ret.getI() + ")"); }
Generated
class
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35. Running the Client
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36. Additional (Advanced!) Features
SOAP with Attachments
Custom type mappings (Pluggable Serializers)
One-way invocations
Document exchange
Dispatch to EJBs
HTTPS transport and mutual authentication
Username and password based authentication …
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37. Where to find more information?
Apache Axis Home:
Sun’s Web Services Developer Pack Home:
W3C’s Web Services Activity Home Page:
My Home Page:
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38. Thank
You
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