Intro to Apache Axis (1)

8/4/2019 Intro to Apache Axis (1)

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Antaryami SahooSlides 45

Duration 1 hr


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Web Services Basics Intro to Apache Axis


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Web Services Basics What is Web Service? Web Services Architecture

Ways to develop Web services XML Messaging XML-RPC

SOAP

What is WSDL? Development plan for Service Requestor Development plan for Service Provider


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Intro to Apache Axis What is Apache Axis?

Features of Apache Axis

Installing Apache Axis

Publishing Web Service through Apache Axis

Walkthrough of deploying and accessing a simpleweb service using Apache Axis


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A Web Service is any service that is available over the web

uses standardized XML messaging

is OS and Programming language independent


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There are two ways we can view WebServices

architecture

1. Web Service Roles

2. Web Service Protocol Stack


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There are three major roles

Service

Registry

Service

Requestor

Service

Provider

2) Discover services

3) Invoke service

Provider of the Web ServiceConsumer of the Web Service

Logically Centralized directory

of services

1) Register service


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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


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1. REST2. SOAP

REST ( Representative State Transfer) : In RESTful web services, the emphasis is on simple point-to-

point communication over HTTP using plain old XML It uses protocol methods for its operations like :

HTTPCRUD Equivalent :-GET readPOST updatePUT createDELETE delete


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There are two ways of XML Messaging

XML-RPC

SOAP


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is a simple protocol that uses XMLmessages to perform RPC

Request are encoded in XML and send viaHTTP

Response are encoded in XML andreceived via HTTP

is a easiest way to get started with webservices


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com.agram.sayHello

Java


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Hello Java


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Simple Object Access ProtocolSOAP is slightly more complicated than

the XML-RPCSOAP extended XML-RPC It uses XML namespaces and XML

Schemas.


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Envelope is like awrapper for content

Header is a optionalelement that could contain

control information Body element includes

requests and responses Body element will include

a Fault element in theevent of an error

SOAP Message

Envelope

Header

Body


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GET /StockPrice HTTP/1.1Host: example.orgContent-Type: application/soap+xml; charset=utf-8Content-Length: nnn

IBM


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HTTP/1.1 200 OKContent-Type: application/soap+xml; charset=utf-8Content-Length: nnn

45.25


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The is the standard element for error handling. When present, itis the only child element of the SOAP . The structure of a faultlooks like:

env:Sender

m:MessageTimeout

Sender Timeout

P5M


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Web Services Description Language

An XML-based language for describingWeb Services

what the service does (description) how to use it (method signatures)

where to find the service

It does notdepend on the underlyingprotocol

But: It is not much human-readable


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Has 6 major elements1. definitions defines the name of the web service

2. types describes all the data types that will betransmitted

3. message defines the name of the message thatwill be transmitted

4. portType defines the operations

5. binding defines how the message will be

transmitted6. service defines where the service is located


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Universal Description, Discovery and

Integrationhttp://www.uddi.org

UDDI creates a platform-independent, open framework &

registry for:

Describing services

Discovering businesses

Integrating business services

The UDDI may be less used than predicted, especially onthe Internet level


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1) Find web service via UDDI

2) Retrieve service description file

3) Create XML-RPC or SOAP client

4) Invoke remote service


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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


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Axis is essentially a SOAP engine aframework for constructing SOAPprocessors such as clients , servers,gateways etc

- Axis Website


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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


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1) Download Axis Distribution archive fromhttp://xml.apache.org/axis/

- Axis distribution archive containsa web application ( webapps/axis/directory) for hosting an Axis Server in a

web container like Tomcat
http://xml.apache.org/axis/http://xml.apache.org/axis/


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2) Deploy Axis Server in the Tomcat 5.Xserver

a) Copy Axis Web application (webapps/axisdirectory) to $TOMCAT_HOME/webapps

b) Copy jaxrpc.jar (that is provided with Axisdistribution) and xerces.jar ( or any other XMLparser) to $TOMCAT_HOME/common/lib

jaxrpc.jar and xerces.jar includes classes with java andjavax packages and Tomcat does not authorize to load any classes

in that package from WEB-INF/ lib directory of the web application.


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3) Configure the environment by includingthese libraries in the CLASSPATH

- log4j-core.jar- commons-logging.jar- wsdl4j.jar- jaxrpc.jar- tt.bytecode.jar- xerces.jar ( or any other XML Parser)


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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 running3) Goto http://localhost:8080/axis/happyaxis.jsp

- this test page verifies whether all the needed andoptional libraries are present.

- Axis will not perform properly until all theneeded libraries are present.
http://localhost:8080/axis/http://localhost:8080/axis/happyaxis.jsphttp://localhost:8080/axis/happyaxis.jsphttp://localhost:8080/axis/


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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)


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1. Code code a simple HelloWorld java class that wewant to expose as web service

2. Java2WSDL Generate the WSDL file for the givenHelloWorld Interface

3. WSDL2Java Generate the Server side wrapperclass and stubs for easy client access

4. Deploy deploy the service to apache axis

5. Client code a simple client that access ourHelloWorld Web Service


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HelloWorld.java

package helloworld;

public interface HelloWorld {public String sayHello( String name);

}


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HelloWorldImpl.java

package helloworld;

public class HelloWorldImpl implements HelloWorld {

public String sayHello( String name){if(name == null)

return Hello Everyone;else

return Hello + name;}

}


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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-phelloworld" urn:helloworldhelloworld.HelloWorld

Parameters description-o = Name of the output-l = URL of the web Service-n = Target Namespace for the WSDL

-p = Map Java package to namespaceFully Qualified Class Name


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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.genhello.wsdl

Parameters description-o = Base output Directory-d = Scope of deployment

-s = To generate Server-side code too-p = Package to place the codeName of the WSDL


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These are the codes that will get generated1. 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 fromthe Axis System


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HelloWorldSoapBindingImplpackage helloworld.gen;

public class HelloWorldSoapBindingImpl implementshelloworld.gen.HelloWorld

{

public String sayHello(String str0) throwsjava.rmi.RemoteException {

}}

import helloworld.HelloWorldImpl;

HelloWorldImpl helloWorld = new HelloWorldImpl();

return helloWorld.sayHello(str0);


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1. 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 Done processing


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package helloworld;

Import helloworld.gen.*;public class HelloWorldTester {

public static void main(String [] args)throws Exception

{// Make a service

HelloWorldService service = newHelloWorldServiceLocator();// Now use the service to get a stub to the servicehelloworld.gen.HelloWorld hello = service.getHelloWorld();// Make the actual callSystem.out.println( hello.sayHello(Java Gurus) );

}

}


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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 usingApache Axis


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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
http://java.sun.com/j2ee/webservices/index.htmlhttp://java.sun.com/xml/docs.htmlhttp://xml.apache.org/axis/index.htmlhttp://www.w3.org/TR/SOAPhttp://www.w3.org/TR/wsdlhttp://www.w3.org/TR/wsdlhttp://www.w3.org/TR/SOAPhttp://xml.apache.org/axis/index.htmlhttp://java.sun.com/xml/docs.htmlhttp://java.sun.com/j2ee/webservices/index.html


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Intro to Apache Axis (1)