The DBCP Component

Many Apache projects support interaction with a relational database. Creating a new connection for each user can be time consuming (often requiring multiple seconds of clock time), in order to perform a database transaction that might take milliseconds. Opening a connection per user can be unfeasible in a publicly-hosted Internet application where the number of simultaneous users can be very large. Accordingly, developers often wish to share a "pool" of open connections between all of the application's current users. The number of users actually performing a request at any given time is usually a very small percentage of the total number of active users, and during request processing is the only time that a database connection is required. The application itself logs into the DBMS, and handles any user account issues internally.

There are several Database Connection Pools already available, both within Apache products and elsewhere. This Commons package provides an opportunity to coordinate the efforts required to create and maintain an efficient, feature-rich package under the ASF license.

The commons-dbcp2 artifact relies on code in the commons-pool2 artifact to provide the underlying object pool mechanisms.

DBCP now comes in four different versions to support different versions of JDBC. Here is how it works:

Developing

• DBCP 2.5.0 and up compiles and runs under Java 8 (JDBC 4.2) and up.
• DBCP 2.4.0 compiles and runs under Java 7 (JDBC 4.1) and above.

Running

• DBCP 2.5.0 and up binaries should be used by applications running on Java 8 and up.
• DBCP 2.4.0 binaries should be used by applications running under Java 7.

DBCP 2 is based on Apache Commons Pool and provides increased performance, JMX support as well as numerous other new features compared to DBCP 1.x. Users upgrading to 2.x should be aware that the Java package name has changed, as well as the Maven co-ordinates, since DBCP 2.x is not binary compatible with DBCP 1.x. Users should also be aware that some configuration options (e.g. maxActive to maxTotal) have been renamed to align them with the new names used by Commons Pool.

Releases

See the downloads page for information on obtaining releases.

Documentation

The Javadoc API documents are available online. In particular, you should read the package overview of the org.apache.commons.dbcp2 package for an overview of how to use DBCP.

There are several examples of using DBCP available.