These are the steps that I took in order to get the "news-app" EJB working
on Orion 8.2, with JDK1.2. It is just a matter of making sure all the
necessary steps have been completed, which is not always an easy task.
Hopefully this document will help - let me know if there are any questions.
This is not a tutorial, so it won't contain any code.
Getting the news-app EJB working
First of all, you need to have a database for your entity Beans. For the
news-app example, you can use the Hypersonic Database at
http://www.lynx.ch/Contacts/~/ThomasM/hypersql.html. Download the
hsql.zip file and unzip it in the orion directory, and make sure that the
directory structure of hsql/hDriver.class (found in hypersonic/demo) is in
the orion classpath, such as c:\orion or c:\orion\lib. When this is
complete, you can proceed with the following steps of deploying the news-app
EJB.
1) Add a valid data-source to config/data-sources.xml and uncomment
the helper datasources in the same file:
Make sure your data-source looks like this, and uncomment the rest of the
file:
<data-source class="com.evermind.sql.ConnectionDataSource"
location="jdbc/DefaultDS">
<name>Default data-source</name>
<description>
Hypersonic SQL source.
</description>
<url>jdbc:HypersonicSQL:defaultdb</url>
<connection-driver>hSql.hDriver</connection-driver>
<username>sa</username>
<password></password>
</data-source>
2) Make sure the <ejb-config> and <rmi-config> tags are uncommented in
config/server.xml.
4) Close the comment on line 16 of config/server.xml: <!-- RMI-server
config link, uncomment to activate the RMI service - (if it is not already
closed.)
5) Install the EJB: this is done by uncommenting the <ejb-jar> entry in
config.xml/ejb.xml that is used for the news-app.
6) Uncomment the <web-app> tag to the news-app in
c:\orion\default-site\web-site.xml, so you can run the EJB with JSP.
7) Remove the status="deactivated" parameters from config/principals.xml.
(If you get a mysterious login page in the demos, it refers to these
<user> entries)
8) Restart Orion to auto-deploy the EJB.
*Note: The first time your entity Bean is deployed, which is also the
creation of the database, you should see some server output like this, which
shows confirmation of the deployed EJB, and the name of the DB table:
C:\orion>java -jar orion.jar
Auto-deploying file:/C:/orion/demo/news-app/news-ejb/...
Auto-creating table: create table com_evermind_ejb_NewsItem (id INTEGER
primarykey, subject VARCHAR (255), text VARCHAR (255), date TIMESTAMP,
submitter VARCHAR (255), locale VARCHAR (5))
done.
Orion/0.8.2 initialized
After the Entity Bean is deployed, we can now access it.
1) A good way to see what's going on is to access the EJB by going to
C:\orion\demo\news-app\news-ejb\com\evermind\ejb and run the NewsItemClient
(java com.evermind.ejb.NewsItemClient). Also, make sure that
c:\orion\demo\news-app\news-ejb is in your classpath. This client will ask
the user for input items that will be used in an ejbCreate() method, which
will map those entity Bean values to persistent records in a database (you
can verify this later).
2) After running the client, you now have used an Entity Bean to map data
into a database, making it persistent, and now that data is available
anywhere at anytime, and should be at no risk of being lost or corrupted
thru EJB.
3) Now go to http://localhost:2000/news/border.html, and select the "view"
hyperlink, which will take you to http://localhost:2000/news/news.jsp, which
is essentially displaying all data in the database to you, by calling an EJB
findAll().
4) If you just want to see the generic raw data in the database, the
database is written to the file system in c:\orion\defaultdb, so you can use
Hypersonic's DatabaseManager tool (Java application) to run simple select
statements to query the database whether the Orion application server is
running or not, just to show you that your data is in the database.
And that's it - you have now seen how data is persisted with Enterprise Java
Beans, which shows the power of EJB, and the power of the EJB Server, Orion.
>From here, you should be able to now create your own entity Beans and use
your own database to productively use EJB.
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