C-puter: Web Services

9/06/2005

Web Services

At work I have been trying to learn web services. On my machine I have installed: the Java sdk, J2EE, Eclipse, MySQL, SQL Explorer extension for Eclipse, J/Connector, Tomcat, Java WSDP, WTP, Axis, Apache web server and some other stuff that were required to run some Eclipse plugins. Yuck, yuck, yuck. Here are some notes that I have made. Web Services with Java (JAX pack) JAXP: SAX API, DOM, XSLT (read and write XML documents)

mechanism for plugging in various providers supporting DOM, SAX and XSLT
mechanism to specify which provider to use

JAX-RPC: SOAP, provides ability to generate WSDL from a Java interface and vice versa, generates client side stubs Creating a JAX-RPC Client

obtain instance of interface stub
set endpoint property of stub to the service endpoint of the web service
call method

JAXM: way of sending XML docs over the internet, works with ebXML

Asynchronous: client must wait for a reply before continuing
Asynchronous, with acknowledgement (ack)
Synchronous: reply isn't required
Synchronous with ack
Fire and forget

Developing a JAXM Servlet

import required packages
implement AsynchListener or SyncListener
implement on Message method
obtain SOAP message
obtain SOAP envelop/attachment and to do stuff with them
return SOAP message

Building a message producer

create a connection
obtain a message from a message factory
populate the message
send message

JAXR: access registries Registries

White Pages: directory of names
Yellow Pages: directory by category/service
Green Pages: categorized by service type or specification (DOM, SAX)

Searching a registry

create a connection
obtain a handle to a Registry Service
obtain query manager from Registry Service
use query manager to perform queries

JAXB: binds XML into Java and vice versa Notes on the Ant/WSDP install:

change directory to the folder where ant.jar is located
add the path where ant.jar is located to environment variables (ANT_HOME)
type ant change-database -Ddatabase=mysql -s PATH
PATH isn't the full path, just the path from the directory in which WSDP is installed (jwsdp-1.6)

In each of the JAX pack folders is documentation for each one of the APIs. To excute a JAXRPC program, go to apache-ant\bin\ and enter the command: ant deploy-war -s \jaxrpc\samples\helloworld\build.xml To use MySQL with JDBC, you need J/Connector. SQL Explorer works as an Eclipse plugin. I downloaded the mysql folder into the project folder that I am working in in order to connect to my local MySQL database. Web Services Vocabulary (just keep in mind all of those terms about Operating System messaging) Endpoint: a specific location for accessing a Web Service using a protocol and data format (like a socket) Unmarshall: converting XML data into a tree of Java content objects Marshall: converting a Java content tree into an XML document Validator: determines whether java classes conform to schema Dispatchers: map XML data to Java objects DII: static/dynamic stub Stub: object that runs on a server that acts as a channel for all communication between the server and a remote client To customize bindings means to change the java classes/objects various XML namespaces correspond to.

// posted by jessi @ 7:18 PM

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