Matt RaibleMatt Raible is a Java Champion and Developer Advocate at Okta. developer.okta.com

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10+ YEARS


Over 10 years ago, I wrote my first blog post. Since then, I've authored books, had kids, traveled the world, found Trish and blogged about it all.

Upgrading from Tyrex 0.9.7 to Commons DBCP.

I'm trying to upgrade from Tyrex 0.9.7 (ships with Tomcat 4.0.4 for connection pooling) to the Commons DBCP (ships with Tomcat 4.1.x for connection pooling). I've set it up according to these instructions. However, my connections don't seem to be getting closed, or it's closing the connection pool and I get a "connection is closed" error.

If I use this method to close connections, I get "connection is closed:"

    /** Closes a connection from the connection pool */
    public void closeConnection(Connection con) throws ServiceLocatorException
    {
        try {
            con.close();
        } catch (SQLException sqle) {
            logger.error("SQLException: " + sqle.getMessage());
            throw new ServiceLocatorException(sqle);
        } finally {
            if (con != null) {
                // try again
                try {
                    con.close();
                } catch (SQLException csqle) {
                    // ignore
                }
            }
        }
    }

I changed my closeConnection method (see below). It seems to work better (no closed connection error), but I am wondering about the open connections to mysql. When I monitor them (show status; watch Threads_connected), there are 3 at first (I'm guessing from my monitor connection, JDBCRealm and Connection pool). It gets up to 5, any tips on how I can tell if connection pooling is working?

    /** Closes a connection from the connection pool */
    public void closeConnection(Connection con) throws ServiceLocatorException
    {
        try {
            con.close();
        } catch (SQLException sqle) {
            logger.error("SQLException: " + sqle.getMessage());
            throw new ServiceLocatorException(sqle);
        } finally {
            // try again
            try {
                if (!con.isClosed()) {
                	con.close();
                }
            } catch (SQLException csqle) {
                // ignore
            }
        }
    }

I think the problem is that it's not creating a "pooled" connection. When you are using a connection pool, con.close() should just return it, not actually close it - right?

In my getPooledConnection method, I'm getting "Non-Pooled Connection" each time.

    /** 
     * Retrieves a connection from the connection pool
     */
    public Connection getPooledConnection() throws ServiceLocatorException
    {
        try {
            ds = (DataSource) getEnvContext().lookup(Constants.JNDI_DB);
        } catch (NamingException ex) {
            logger.error("NamingException: " + ex.getMessage());
            throw new ServiceLocatorException(ex);
        }
        
        try {
            if (ds instanceof ConnectionPoolDataSource) {
                ConnectionPoolDataSource poolDataSrc = (ConnectionPoolDataSource) ds;
                PooledConnection pc = poolDataSrc.getPooledConnection();
                con = pc.getConnection();
                if (logger.isDebugEnabled()) {
                    logger.debug("Pooled Connection");
                }
            } else {
                if (logger.isDebugEnabled()) {
                    logger.debug("Non-Pooled Connection");
                }
                con = ds.getConnection();
            }
        } catch (SQLException ex) {
            logger.error("SQLException: " + ex.getMessage());
            throw new ServiceLocatorException(ex);
        }
        return con;
    }

If you have a WAG/suggestion, please enlighten me!

Posted in Java at Aug 24 2002, 04:12:15 AM MDT Add a Comment
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