Connection Pooling with Commons DBCP PoolingDriver

JDBC for SQL Server - Herong's Tutorial Examples

∟Connection Pooling with Commons DBCP PoolingDriver

This section provides a tutorial example that shows you how to use the Commons DBCP PoolingDriver class to manage the connection pool as a custom JDBC driver.

Another option to use Commons DBCP package for connection pooling is to use the org.apache.commons.dbcp2.PoolingDriver class. It implements the standard JDBC javax.sql.Driver interface to manage the connection pool with a custom JDBC driver.

The steps to build a custom JDBC driver is shown in the setupDriver() methods in the following sample Java program, DbcpPoolingDriverTest.java.

/* DbcpPoolingDriverTest.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;

import org.apache.commons.dbcp2.ConnectionFactory;
import org.apache.commons.dbcp2.DriverManagerConnectionFactory;
import org.apache.commons.dbcp2.PoolableConnectionFactory;
import org.apache.commons.dbcp2.PoolableConnection;
import org.apache.commons.dbcp2.PoolingDriver;

import org.apache.commons.pool2.ObjectPool;
import org.apache.commons.pool2.impl.GenericObjectPool;

public class DbcpPoolingDriverTest {
  static java.io.PrintStream out = System.out;

  public static void main(String[] args) throws Exception {
    String url = "jdbc:sqlserver://localhost\\SQLEXPRESS;"
      + "user=herong;password=T0pSecret";

    // Setup a new PoolingDriver
    setupDriver(url);

    // Get a pooled connection from the new PoolingDriver
    Connection con =
      DriverManager.getConnection("jdbc:apache:commons:dbcp:HyPool");
    checkDriver();

    // Verify the pooled connection
    DatabaseMetaData meta = con.getMetaData();
    out.println();
    out.println("Database Connection Info: ");
    out.println("  Server name: "+meta.getDatabaseProductName());
    out.println("  Server version: "+meta.getDatabaseProductVersion());
    out.println("  Driver name: "+ meta.getDriverName());
    out.println("  Driver version: "+ meta.getDriverVersion());
    out.println("  JDBC major version: "+ meta.getJDBCMajorVersion());
    out.println("  JDBC minor version: "+ meta.getJDBCMinorVersion());

    // Close the pooled connection
    con.close();
    checkDriver();

    // Wait for 3 minutes to check the server side
    out.println();
    out.println("Go and count connections on the database server ...");
    Thread.sleep(3*60*1000);

    // Destroy the PoolingDriver
    destroyDriver();
  }

  public static void setupDriver(String url) throws Exception {

    // Get DBCP's ConnectionFactory based ConnectionFactory
    ConnectionFactory cf = new DriverManagerConnectionFactory(url);

    // Convert it to a PoolableConnectionFactory
    PoolableConnectionFactory pcf =
      new PoolableConnectionFactory(cf, null);

    // Create an ObjectPool with the PoolableConnectionFactory
    ObjectPool<PoolableConnection> op = new GenericObjectPool<>(pcf);

    // Set the factory's pool property to the owning pool
    pcf.setPool(op);

    // Load DBCP's PoolingDriver
    Class.forName("org.apache.commons.dbcp2.PoolingDriver");

    // Register the pool in the PoolingDriver
    PoolingDriver driver =
      (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:");
    driver.registerPool("HyPool", op);

    // The pool is ready as new JDBC driver:
    // "jdbc:apache:commons:dbcp:HyPool"
  }

  public static void destroyDriver() throws Exception {
    PoolingDriver driver =
      (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:");
    driver.closePool("HyPool");
  }

  public static void checkDriver() throws Exception {
    PoolingDriver driver =
      (PoolingDriver) DriverManager.getDriver("jdbc:apache:commons:dbcp:");
  ObjectPool<? extends Connection> op = driver.getConnectionPool("HyPool");
    out.println();
    out.println("DBCP PoolingDriver Info: ");
    out.println("   Active Connections: " + op.getNumActive());
    out.println("   Idle Connections: " + op.getNumIdle());
  }
}

Again, to run this test program against the SQL Server server, I need SQL Server JDBC, DBCP, and 2 other supporting JAR files. See other tutorials to download them.

Let's run it:

herong> java -cp .:\
  commons-dbcp2-2.8.0.jar:\
  commons-pool2-2.10.0.jar:\
  commons-logging-1.2.jar:\
  mssql-jdbc-9.4.1.jre16.jar \
  DbcpPoolingDriverTest.java

DBCP PoolingDriver Info:
   Active Connections: 1
   Idle Connections: 0

Database Connection Info:
   Server name: Microsoft SQL Server
   Server version: 15.00.2000
   Driver name: Microsoft JDBC Driver 9.4 for SQL Server
   Driver version: 9.4.1.0
   JDBC major version: 4
   JDBC minor version: 3

DBCP PoolingDriver Info:
   Active Connections: 0
   Idle Connections: 1

Go and count connections on the database server ...

On the SQL Server server, log in as "root". I see 1 connection as expected.

1> SELECT loginame, COUNT(dbid) FROM sys.sysprocesses
2> GROUP BY dbid, loginame;
3> GO

loginame
------------------------------------ ------
DESKTOP\Admin                             1
Herong                                    1
NT SERVICE\SQLTELEMETRY$SQLEXPRESS        1
sa                                       13
sa                                       39

(5 rows affected)

So, what we can see from this tutorial:

Commons DBCP PoolingDriver allows you to register a new custom JDBC driver to represent an ObjectPool created with the PoolableConnectionFactory class.
There seems to be no limit on the number connections in the pool.
You can easily change the connection URL to test Commons DBCP for connection pooling with MySQL or Oracle.