I tried to use Tomcat's datasource pool via JNDI, but things not going well.
I got the following exception when I tried to get connection:
org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of class '
' for connect URL 'null', cause:
java.lang.NullPointerException
at java.util.StringTokenizer.<init>(StringTokenizer.java:146)
at org.postgresql.Driver.parseURL(Driver.java:251)
at org.postgresql.Driver.acceptsURL(Driver.java:159)
at java.sql.DriverManager.getDriver(DriverManager.java:232)
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSou
rce.java:743)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource
.java:518)
at cpool.struts.action.LogonAction.testJNDI(LogonAction.java:185)
at cpool.struts.action.LogonAction.execute(LogonAction.java:60)
....................................................
....................................................
In struts-config.xml, I added the following:
<data-source>
<set-property property="autoCommit" value="false"/>
<set-property property="description" value="Data Source Configuration"/>
<set-property property="driverClass" value="org.postgresql.Driver"/>
<set-property property="maxCount" value="4"/>
<set-property property="minCount" value="2"/>
<set-property property="password" value=""/>
<set-property property="url" value="jdbc:postgresql:cpool"/>
<set-property property="user" value="cpool"/>
</data-source>
In server.xml:
<Resource name="jdbc/CPool" auth="Container" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/CPool">
<parameter>
<name>username</name>
<value>cpool</value>
</parameter>
<parameter>
<name>password</name>
<value></value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>org.postgresql.Driver</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:postgresql:cpool</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>8</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>4</value>
</parameter>
</ResourceParams>
Then, I wrote the following method in an Action to test the connection:
public void testJNDI()
{
try
{
Context initCtx = new InitialContext();
Context envCtx = (Context)initCtx.lookup("java:comp/env");
if (envCtx != null)
{
TTools.consolePrint("LogonAction", "envCtx", envCtx.toString());
}
//DataSource ds = (DataSource)envCtx.lookup("jdbc/CPool");
DataSource ds =
(DataSource)initCtx.lookup("java:comp/env/jdbc/CPool");
Connection conn = ds.getConnection();
if (conn != null)
{
TTools.consolePrint(conn, "Conn", conn.toString());
}
conn.close();
}
catch (NamingException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (SQLException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Does this problem sounds familiar to you ?
Please give some advice on this, thanks in advance.
bruce
----- Original Message -----
From: "Vic Cekvenich" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, November 03, 2003 3:18 AM
Subject: Re: What's the best choice for connection pooling with Struts and PostgreSQL
> 1. It is a good practice to use the containers data source pool via
> JNDI. Application servers like Tomcat, Resin, OrionServer, etc all
> provide a "service" to the web app of a connection pool. You should not
> code one, but use one.
> Ex:
> Context ctx = new InitialContext();
> DataSource ds = (DataSource) ctx.lookup("java:comp/env/mypool");
> conn = ds.getConnection();
>
> And you configure the pool in the container. Ex in Resin 3.03:
> <database>
> <jndi-name>mypool</jndi-name>
> <driver type="org.postgresql.jdbc3.Jdbc3ConnectionPool" >
> <user>bpuser</user>
> <password>changeme</password>
> <serverName>3.3.3.3</serverName>
> <databaseName>dbname</databaseName>
> </driver>
> <max-connections>3</max-connections>
> </database
>
> The idea here is that you deploy same web app to staging or production,
> without changing the app.
>
> 2. You do not need to do #1 above either. Just like you use Struts and
> not code to servlets, you should not code to JDBC. You should use a DAO,
> such as iBatis.com (SQL based and my favorite) or Hibrenate.
> Ex in iBatis:
> List _resList;
> _sqlMap.startTransaction();
> _resList = _sqlMap.executeQueryForList("xmlNamedSQLquerry");
>
> And you have a List of results. The JNDI, pool open and close it done
> for you, you just work on your result list (that you can pass on to
> display tag for example)
>
> J2EE designed real nice and you should leverage it, not fight it.
>
> hth,
>
>
>
> ZYD wrote:
> > Dear all,
> >
> > I'm writing my Struts application using PostgreSQL as the backend database. Could
> > you give me some advice on choosing the connection pooling framework/methods?
> >
> > I wrote my own connection pooling classes, but if there are some good frameworks
> > from jakarta, it definitely worth a try.
> >
> > Any response is greatly appreciated.
> >
> > bruce
> >
>
> --
> Victor Cekvenich,
> Struts Instructor
> (215) 321-9146
>
> Advanced Struts Training
> <http://basebeans.com/do/cmsPg?content=TRAINING> Server Side Java
> training with Rich UI, mentoring, designs, samples and project recovery
> in North East.
> Simple best practice basic Portal, a Struts CMS, Membership, Forums,
> Shopping and Credit processing, <http://basicportal.com> software, ready
> to develop/customize; requires a db to run.
>
>
>
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