intro to apache axis siva jagadeesan [email protected]
TRANSCRIPT
Intro to Apache AxisIntro to Apache Axis
Siva Jagadeesan [email protected]
About MeAbout Me
I am a Java Consultant working in a project for Deloitte Consulting
My fields of Expertise– J2EE Technologies
– Java tools for Extreme Programming (Ant, JUnit etc) My fields of Interest
– Web Services
– J2ME
– Aspect Oriented Programming
AgendaAgenda
Web Services BasicsIntro to Apache Axis
OutlineOutline
Web Services Basics– What is Web Service?– Web Services Architecture– XML Messaging
XML-RPCSOAP
– What is WSDL?– Development plan for Service Requestor– Development plan for Service Provider
OutlineOutline
Intro to Apache Axis– What is Apache Axis?– Architecture of Apache Axis– Features of Apache Axis– Installing Apache Axis– Publishing Web Service through Apache Axis– Walkthrough of deploying and accessing a
simple web service using Apache Axis
What is Web Service?What is Web Service?
A Web Service is any service that – is available over the web– uses standardized XML messaging– is OS and Programming language
independent
Web Services ArchitectureWeb Services Architecture
There are two ways we can view Web Servicesarchitecture
1. Web Service Roles
2. Web Service Protocol Stack
Web Service RolesWeb Service Roles
There are three major roles
Service Registry
Service Requestor
ServiceProvider
2) Discover services
3) Invoke service
Provider of the Web Service Consumer of the Web Service
Logically Centralized directory of services
1) Register service
Web Service Protocol StackWeb Service Protocol Stack
Discovery UDDI
Description WSDL
XML Messaging XML-RPC,SOAP,XML
Transport HTTP,SMTP,FTP,BEEP
Responsible for centralizing services
Responsible for transporting messages
Responsible for describing the public interface to a specific web service
Responsible for encoding messages in common XML format
XML MessagingXML Messaging
There are two ways of XML Messaging
• XML-RPC
• SOAP
What is XML-RPC ?What is XML-RPC ?
is a simple protocol that uses XML messages to perform RPC
Request are encoded in XML and send via HTTP
Response are encoded in XML and received via HTTP
is a easiest way to get started with web services
Sample XML-RPC RequestSample XML-RPC Request
<methodCall><methodName>
com.agram.sayHello</methodName>
<params><param>
<value>Java</value></param>
</params></methodCall>
Sample XML-RPC ResponseSample XML-RPC Response
<methodResponse> <params>
<param><value>
<string>Hello Java</string></value>
</param> </params></ methodResponse >
What is SOAP?What is SOAP?
Simple Object Access ProtocolSOAP is slightly more complicated than
the XML-RPCSOAP extended XML-RPCIt uses XML namespaces and XML
Schemas.
SOAP MessageSOAP Message
Envelope is like a wrapper for content
Header is a optional element that could contain control information
Body element includes requests and responses
Body element will include a Fault element in the event of an error
SOAP Message
Envelope
Header
Body
Sample SOAP RequestSample SOAP Request
<SOAP-ENV:Envelopexmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:SOAP-ENV=http://schemas.xmlsoap.org/soap/envelope/
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<SOAP-ENV:Body> <ns1:sayHello xmlns:ns1="http://agram.com/"> <name xsi:type="xsd:string">Java</name></ns1:sayHello>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
Sample SOAP ResponseSample SOAP Response
<SOAP-ENV:Envelopexmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:SOAP-ENV=http://schemas.xmlsoap.org/soap/envelope/ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<SOAP-ENV:Body> <ns1:sayHelloReponse xmlns:ns1="http://agram.com/"> <result xsi:type="xsd:string">Hello Java</result>
</ns1:sayHelloResponse> </SOAP-ENV:Body>
</SOAP-ENV:Envelope>
What is WSDL?What is WSDL?
Web Services Description Language Has 6 major elements
1. definitions – defines the name of the web service2. types – describes all the data types that will be
transmitted3. message – defines the name of the message that will
be transmitted4. portType – defines the operations 5. binding – defines how the message will be
transmitted6. service – defines where the service is located
Development plan for Service RequestorDevelopment plan for Service Requestor
1) Find web service via UDDI
2) Retrieve service description file
3) Create XML-RPC or SOAP client
4) Invoke remote service
Development plan for Service ProviderDevelopment plan for Service Provider
1) Create the core functionality
2) Create XML-RPC or SOAP service wrapper
3) Create service description file
4) Deploy service
5) Register new service via UDDI
What is Apache Axis?What is Apache Axis?
“Axis is essentially a SOAP engine – a framework for constructing SOAP processors such as clients , servers, gateways etc”
- Axis Website
Architecture of Apache AxisArchitecture of Apache Axis
Architecture of Apache AxisArchitecture of Apache Axis
1. Admin Sub-systemhandles administration and configuration of the server
2. Service Sub-systemimplements the RPC exchange protocol
3. Provider Sub-systemis the interface between Axis server and the external component methods that are to be exposed as webservice
4. Transport Sub-systemreceives and delivers the message from the service sub system
5. Encoding Sub-systemmanages encoding/decoding and serilization/deserilization between XML data types and Java Classes
6. Message Sub-systemdefines the structure of the different elements of a SOAP message and provides functionality for binding and parsing the different elements of these messages
Features of Apache AxisFeatures of Apache Axis
Successor to Apache SOAP It can run as a standalone server or as an a server
that plugs into Servlet engine like Tomcat Automatic WSDL generation for deployed
services Java2WSDL – to generate WSDL from Java
interface WSDL2Java – to generate Java classes from
WSDL Easy deployment Uses JAX-RPC API
Installing Apache AxisInstalling Apache Axis
1) Download Axis Distribution archive fromhttp://xml.apache.org/axis/
- Axis distribution archive contains a web application ( webapps/axis/ directory) for hosting an Axis Server in a web container like Tomcat
Installing Apache Axis (Cont)Installing Apache Axis (Cont)
2) Deploy Axis Server in the Tomcat 4.X server
a) Copy Axis Web application (webapps/axis directory) to $TOMCAT_HOME/webapps
b) Copy jaxrpc.jar (that is provided with Axis distribution) and xerces.jar ( or any other XML parser) to $TOMCAT_HOME/common/lib
jaxrpc.jar and xerces.jar includes classes with “java” and “javax” packages and Tomcat does not authorize to load any classes in that package from WEB-INF/ lib directory of the web application.
Installing Apache Axis (Cont)Installing Apache Axis (Cont)
3) Configure the environment by including these libraries in the CLASSPATH
- log4j-core.jar- commons-logging.jar- wsdl4j.jar- jaxrpc.jar- tt.bytecode.jar- xerces.jar ( or any other XML
Parser)
Validating the InstallationValidating the Installation
1) Start the Tomcat Web Server2) Goto http://localhost:8080/axis/
- you should be able to see Apache-Axis start page- if you did not , then the axis is not correctly installed or the web server is not running
3) Goto http://localhost:8080/axis/happyaxis.jsp- this test page verifies whether all the needed and optional libraries are present.- Axis will not perform properly until all the needed libraries are present.
Publishing Web Service through Apache Publishing Web Service through Apache AxisAxis
The two ways we can publish a web servicewith Axis are,
1. Instant Deployment – Java Web Service (JWS)
2. Custom Deployment – Using Web Service Deployment Descriptor ( WSDD)
Walkthrough of deploying and accessing a Walkthrough of deploying and accessing a simple web service using Apache Axissimple web service using Apache Axis
The steps we will walkthroughThe steps we will walkthrough
1. Code – code a simple HelloWorld java class that we want to expose as web service
2. Java2WSDL – Generate the WSDL file for the given HelloWorld Interface
3. WSDL2Java – Generate the Server side wrapper class and stubs for easy client access
4. Deploy – deploy the service to apache axis
5. Client – code a simple client that access our HelloWorld Web Service
Step 1: CodeStep 1: Code
HelloWorld.java
package helloworld;
public interface HelloWorld { public String sayHello( String name); }
Step 1: Code (Cont)Step 1: Code (Cont)
HelloWorldImpl.java
package helloworld;
public class HelloWorldImpl implements HelloWorld {
public String sayHello( String name){if(name == null)return “Hello Everyone”;elsereturn “Hello “ + name;
}
}
Step 2: Java2WSDLStep 2: Java2WSDL
This command will generate the WSDL thatConforms to our interface% java org.apache.axis.wsdl.Java2WSDL
-o hello.wsdl -l http://localhost:8080/axis/services/helloworld
-n urn:helloworld -p“helloworld" urn:helloworld helloworld.HelloWorldParameters description
-o = Name of the output -l = URL of the web Service -n = Target Namespace for the WSDL -p = Map Java package to namespace Fully Qualified Class Name
Step 3: WSDL2JavaStep 3: WSDL2Java
This command will generate the wrapper code fordeploying the service, as well as client stubs foraccessing it.% java org.apache.axis.wsdl.WSDL2Java
-o . -d Session
-s -p helloworld.gen hello.wsdlParameters description
-o = Base output Directory -d = Scope of deployment -s = To generate Server-side code too -p = Package to place the code Name of the WSDL
Step 3: WSDL2JavaStep 3: WSDL2Java
These are the codes that will get generated
1. HelloWorldSoapBindingImpl.java – This is the implementation code for the Web Service
2. HelloWorld.java – This is the remote interface
3. HelloWorldService.java – This is the service interface
4. HelloWorldServiceLocator.java – Helper class to retrieve handler to service
5. HelloWorldSoapBindingSkeleton.java – Server-side skeleton code
6. HelloWorldSoapBindingStub.java – Client side stub
7. deploy.wsdd – axis deployment descriptor
8. undeploy.wsdd – deployment descriptor to undeploy the web services from the Axis System
Step 3: WSDL2JavaStep 3: WSDL2JavaHelloWorldSoapBindingImplpackage helloworld.gen;
public class HelloWorldSoapBindingImpl implements helloworld.gen.HelloWorld
{
public String sayHello(String str0) throws java.rmi.RemoteException {
}}
import helloworld.HelloWorldImpl;
HelloWorldImpl helloWorld = new HelloWorldImpl();
return helloWorld.sayHello(str0);
Step 4: DeployStep 4: Deploy1. Compile the Service Code
% javac helloworld\gen\*.java
2. Package the code for Axis% jar cvf hello.jar helloworld/*.class helloworld/gen/*.class% mv hello.jar $TOMCAT_HOME/webapps/axis/WEB-
INF/lib
3. Deploy the Service using WSDD% java org.apache.axis.client.AdminClient deploy.wsdd<admin> Done processing </Done>
Step 5: ClientStep 5: Clientpackage helloworld;
Import helloworld.gen.*;
public class HelloWorldTester {
public static void main(String [] args) throws Exception
{ // Make a service HelloWorldService service = new
HelloWorldServiceLocator();
// Now use the service to get a stub to the service helloworld.gen.HelloWorld hello = service.getHelloWorld();
// Make the actual call System.out.println( hello.sayHello(“Java Gurus”) );
} }
SummarySummary
Web Service – Roles in Web Services– Web Services Protocol Stack– Different ways of XML Messaging– Development plan for Service Requestor and Provider
Axis– Architecture of Axis– Features of Apache Axis– Installing Apache Axis– Different ways of deploying Web Service with Axis– Deploying and accessing a simple web service using Apache
Axis
ResourcesResources
JAX-RPC home - http://java.sun.com/xml/jaxrpc/index.html
Web Services & Java home - http://java.sun.com/j2ee/webservices/index.html
Java Web Services tutorial - http://java.sun.com/xml/docs.html#tutorials
Apache Axis - http://xml.apache.org/axis/index.html
SOAP 1.1 - http://www.w3.org/TR/SOAP WSDL 1.1 - http://www.w3.org/TR/wsdl
Questions/Feedbacks?Questions/Feedbacks?
Contact me [email protected]