[jboss-user] [Beginners Corner] - Managed Connection Pools
I am getting the 'NoManagedConnections' Exception this only happens after a while,
but I confess I am confused by the JBoss documentation and the few examples of servlets
working with JBoss don't seem to be much help.
I get a new connection object when I call the init method of each of my servlets (there
are about 20), that is the only connection object I use for that servlet (I pass it as a
parameter to the various factory classes I use within the servlet to do database access).
But if I understand correctly, there is only one instance of each servlet - so it shoud
only be using one connection? So I should only be using the same number of connections as
servlets?
Do I really need to close and create connections whenever I use JDBC?
Is there somewhere I can put a close command that wouldn't be too much rework? Or is
there a timeout for spotting dead connections?
I already have a fairly large application and this would be painful to put it mildly... I
thought that was the point of a managed connection pool? I have included the datasource
XML file and also the code for getting a connection.
Thank-you in advance
Mark
I have project-ds.xml file to set-up a connection pool with Postgres:
| <datasources>
| <local-tx-datasource>
| <jndi-name>MtrdbDS</jndi-name>
| <connection-url>jdbc:postgresql://myserver:5434/myDb</connection-url>
| <driver-class>org.postgresql.Driver</driver-class>
| <user-name>someUser</user-name>
| <password>somepassword</password>
| <metadata>
| <type-mapping>PostgreSQL 8.0</type-mapping>
| </metadata>
| </local-tx-datasource>
|
I use a JNDI call to get a connection from that pool:
| public Connection getConnection() throws SQLException
| {
| Connection conn = null;
| Context ctx = null;
| DataSource ds = null;
| String sourceName = "";
|
| try
| {
| ctx = new InitialContext();
|
| if(ctx == null )
| throw new NamingException("Error 'Db.getConnection' - No
Context");
|
| sourceName = this.getDbName(ctx);
|
| ds = (DataSource)ctx.lookup(sourceName);
| }
| catch (NamingException e)
| {
|
MtrErr.writeExc(MtrErr.OTHER_SOURCE,this.getClass().toString(),"getConnection",e);
| }
| catch (Exception e)
| {
|
MtrErr.writeExc(MtrErr.OTHER_SOURCE,this.getClass().toString(),"getConnection",e);
| }
|
| if (ds != null)
| {
| conn = ds.getConnection();
| }
|
| return(conn);
| }
|
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