JDBC compressed stream

Hi, I'm developing a java client application that uses JDBC to access a
PostGIS/PostgreSQL database. I'm working with PostgreSQL JDBC driver Type 4
(http://jdbc.postgresql.org/) and I need to compress the output streamdata
from database queries.

The problem can't be resolved making a better WHERE clause, because I
have to received a great amount of GIS information, and this info can be
highly compressed. Moreover, this data can't be stored compressed in the
database, so, an external compressor is needed.

Anybody can explain me if it is possible to compress a JDBC datastream
??? Is this a PostgreSQL JDBC driver issue??? or a new function must be
added to PostgreSQL???

Last question --> Anyone knows any other way to achieve compression
with other kind of solution???

Thanks very much... Javier