An interceptor is a software design pattern that provides a transparent way to extend or modify some aspect of a program, similar to a user exit. No recompiling is required. With Connector/J, the interceptors are enabled and disabled by updating the connection string to refer to different sets of interceptor classes that you instantiate.
The connection properties that control the interceptors are explained in Section 5.1, “Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J”:
connectionLifecycleInterceptors, where you
specify the fully qualified names of classes that implement
the
com.mysql.jdbc.ConnectionLifecycleInterceptor
interface. In these kinds of interceptor classes, you might
log events such as rollbacks, measure the time between
transaction start and end, or count events such as calls to
setAutoCommit().
exceptionInterceptors, where you specify
the fully qualified names of classes that implement the
com.mysql.jdbc.ExceptionInterceptor
interface. In these kinds of interceptor classes, you might
add extra diagnostic information to exceptions that can have
multiple causes or indicate a problem with server settings.
Because exceptionInterceptors classes are
only called when handling a SQLException
thrown from Connector/J code, they can be used even in
production deployments without substantial performance
overhead.
statementInterceptors, where you specify
the fully qualified names of classes that implement the
com.mysql.jdbc.StatementInterceptorV2
interface. In these kinds of interceptor classes, you might
change or augment the processing done by certain kinds of
statements, such as automatically checking for queried data in
a memcached server, rewriting slow queries,
logging information about statement execution, or route
requests to remote servers.