Question

I have a series of methods running within a servlet engine (Tomcat in this case), using connection pooling to access the database written in this way:

// Gets an RSS_Feed.
public static RSS_Feed get(int rssFeedNo) {
    ConnectionPool_DB pool = ConnectionPool_DB.getInstance();
    Connection connection = pool.getConnection();
    PreparedStatement ps = null;
    ResultSet rs = null;

    String query = ("SELECT * " +
                    "FROM RSS_Feed " +
                    "WHERE RSSFeedNo = ?;");

    try {
        ps = connection.prepareStatement(query);
        ps.setInt(1, rssFeedNo);
        rs = ps.executeQuery();
        if (rs.next()) {
            return mapRSSFeed(rs);
        }
        else {
            return null;
        }
    }
    catch(Exception ex) {
        logger.error("Error getting RSS_Feed " + rssFeedNo + "\n", ex);
        return null;
    }
    finally {
        Database_Utils.closeResultSet(rs);
        Database_Utils.closeStatement(ps);
        pool.freeConnection(connection);
    }
}

Is it possible to call such a method outside of the servlet engine at all? I would like to do this in a batch process executed from the command line instead of within the servlet engine. I know I could simply rewrite the query without connection pooling but this is one of many queries involved in the process.

The connection pooling is implemented via Apache Common DBCP.

ConnectionPool_DB.getInstance(); reads:

private ConnectionPool_DB() {
    try {
        InitialContext ic = new InitialContext();
        dataSource = (DataSource) ic.lookup(PropertiesFile.getProperty("myApp", "DATASOURCE"));
        // dataSource = (DataSource) ic.lookup("java:/comp/env/jdbc/myApp");
    }
    catch(Exception ex) {
        logger.error("Error getting a connection pool's datasource\n", ex);
    }
}

Answer 1

I have something like this in a project:

Context ctx = new InitialContext(); 
DataSource ds = (DataSource) ctx.lookup("DbConnection");
ConnectionPool connectionPool = new ConnectionPool(ds)

And inside context xml I define the resouce like this

<Resource name="DbConnection" 
auth="SERVLET" 
type="javax.sql.DataSource"  
scope="Shareable"            
driverClassName="**driverClassName**" 
url="**url**" 
username="**username**" 
password="**password**" 
maxActive="10" 
maxIdle="10" 
maxWait="1000"
/>

So I assume you have something similar
If so you need to write code to create the DataSource yourself.

This should help you with that
http://docs.oracle.com/javase/tutorial/jdbc/basics/sqldatasources.html