Accessing DBCP in RequestProcessor class

[Satyajeet Kadam]

i am doing struts application where i creating customized Action servlet by extending RequestProcessor. I want to access the list of countries from datbase and make them avaliable to every entry form. I am using DBCP.
HOw to get Database connection in Customized Action servlet before client makes first request and make them avaliable to every enrey form

[Merrill Higginson]

I'd suggest you do this by creating a class that implements the org.apache.struts.action.Plugin interface and putting your code in the init() method. You would then register the plugin in your struts-config.xml file just as you would the validator plugin or any other plugin. If you do this, your code will run when the Struts ActionServlet initializes.

In your code, I would first get the datasource with the following code:

DataSource dataSource = (DataSource)servlet.getServletContext().getAttribute(Globals.DATA_SOURCE_KEY);

Once you have the collection, I'd suggest putting it in application context so that it is available to all other Action classes and JSPs.

servlet.getServletContext().setAttribute("theCollection", theCollection);

Warning: The DBCP has been deprecated and is no longer availble in version 1.3.5 of Struts. It might be a good idea to get away from DBCP and move to a DataSource stored in JNDI.
[ February 01, 2007: Message edited by: Merrill Higginson ]

[Satyajeet Kadam]

Thanks for the soltion.
Currently i am configuring datasource in struts-config.xml.

Q1)ActionServlet is not bind to Struts-config.xml?
after action servlet is fully intilalized then it get access to struts-congig.xml.so from where it gets access to datasource?

q2)How and where to specfiy jndi ?



<data-sources>
<data-source type="org.apache.tomcat.dbcp.dbcp.BasicDataSource">
<set-property property="driverClassName" value="org.gjt.mm.mysql.Driver" />
<set-property property="url" value="jdbc:mysql://localhost:3306/silicon" />
<set-property property="username" value="root" />
<set-property property="password" value="" />

</data-source>
</data-sources>

[Merrill Higginson]

One of the first things the Struts ActionServlet does when it initializes is to read the struts-config.xml file. It then follows the instructions in the config file and creates objects as needed. If you've specified a DataSource in your config file, the ActionServlet will create it and put it in Application scope. After it is finished with all its configuration tasks, the ActionServlet will call the init method on any plugin classes that are registered in the config file. So, by the time it calls your init method, everything has been initialized.

In answer to your second question: Java Naming and Directory Interfact (JNDI) is a part of the J2EE specification and is supported by every application server. It's considered best practice to register a DataSource in JNDI. Each application server has its own interface for setting up JNDI Datasources. Search for JNDI or DataSource in your App server's documentation and you'll find it.

This link shows how to do it in Tomcat 5.

[Milan Jagatiya]

Warning: The DBCP has been deprecated and is no longer availble in version 1.3.5 of Struts. It might be a good idea to get away from DBCP and move to a DataSource stored in JNDI.

Yeah...thats true..DBCP has been deprecated in version 1.3.5 of Struts.

create context.xml file under your META-INF directory ...

<Context path="/rootpath" docBase="webappname" debug="5" >
 
<Resource name="jdbc/myDB" auth="Container"
type="javax.sql.DataSource"
factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"
      driverClassName="DB driver signature"
              url="db url"
username="username" password="password" maxWait="1000"
removeAbandoned="true" maxActive="30" maxIdle="10"
removeAbandonedTimeout="60" logAbandoned="true" />
 
<ResourceLink name="jdbc/myDB" type="javax.sql.DataSource"
global="jdbc/myDB" />
</Context>
 

and append below lines in your web.xml file
 
<resource-ref>
<description>connection pool for strutsdemo1 db</description>
<res-ref-name>jdbc/myDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
 

enjoy....