RE: NEWBIE: flexible declaration of a database URL

[STOCKHOLM, Raymond]

Use tomcat's pooling mecanism : 
in $TOMCAT/conf/server.xml, in your application Context, declare a Resource :

<Context path="/yourapp" docBase="yourapp">
                <Manager className="org.apache.catalina.session.StandardManager"
                        pathname="">
                </Manager>
                <Resource name="jdbc/YOUR_DATABASE" scope="Shareable" 
type="javax.sql.DataSource"/>
                <ResourceParams name="jdbc/YOUR_DATABASE">

                        <parameter>
                        <name>factory</name>
                        <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
                        </parameter>
                        <parameter>
                        <name>maxActive</name>
                        <value>100</value>
                        </parameter>
                        <parameter>
                        <name>maxIdle</name>
                        <value>30000</value>
                        </parameter>
                        <parameter>
                        <name>maxWait</name>
                        <value>100</value>
                        </parameter>

                        <parameter>
                        <name>username</name>
                        <value>sa</value>
                        </parameter>

                        <parameter>
                        <name>password</name>
                        <value>sa</value>
                        </parameter>

                        <parameter>
                        <name>driverClassName</name>
                        <value>com.microsoft.jdbc.sqlserver.SQLServerDriver(your 
driver)</value>
                        </parameter>

                        <parameter>
                        <name>url</name>
                        <value>your.url.with.correct.driver</value>

                        </parameter>

                        <parameter>
                        <name>validationQuery</name>
                        <value>select getdate()</value>
                        </parameter>

                </ResourceParams>
</Context>


You can, in your servlet, access the datasource  :
try {
        Context ctx = new InitialContext();
        this.dataSource = (DataSource) ctx.lookup("java:comp/env/jdbc/YOUR_DATABASE");
} catch (NamingException e) {
        log.error("Constructor throws NamingException " + e.getMessage());
}


And then get a connection from it :
Connection conn = dataSource.getConnection();




-----Message d'origine-----
De : frederik gens [mailto:[EMAIL PROTECTED]
Envoy� : vendredi 18 juin 2004 11:20
� : [EMAIL PROTECTED]
Objet : NEWBIE: flexible declaration of a database URL


Hello,
 
I'm currently developing a JSP/Servlet/JDBC application with Tomcat. In several 
classes called by servlets, I declare the URL which identify the database in order to 
open the connection. 
 
My question is: what is the best way to declare this URL only once, for example in a 
file, or in an environment variable. Therefore, the classes always call this variable. 
Changing the place of the database just requires to change the URL in one place.
 
Thanks in advance!
Frederik

                
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