java调用postgresql,如何用Java调用PostgreSQL程序？

How to make query like this in Java and get the results:

SELECT filedata.num,st_area(ST_Difference(ST_TRANSFORM(filedata.the_geom,70066),filedata_temp.the_geom))

FROM filedata, filedata_temp

Where filedata.num=filedata_temp.num

Or, I think will be better if I create procedure in Postgres from this query.

CREATE OR REPLACE FUNCTION get_geom_difference()

RETURNS void AS

$$

BEGIN

SELECT filedata.num,st_area(ST_Difference(ST_TRANSFORM(filedata.the_geom,70066),filedata_temp.the_geom))

FROM filedata, filedata_temp

Where filedata.num=filedata_temp.num

end;

$$

LANGUAGE 'plpgsql'

and call it

Connection ce_proc= null;

ce_proc = DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgis","postgres","123456");

java.sql.CallableStatement proc = ce_proc.prepareCall("{get_