JAVA Mapping

HI!
This may be a more like a Java question.
I wanted to map postgresql DB to Java.
The way I am doing...

class - customer : this is base class.

class - customerList extends customer has methods
public customer fromResultset(Resultset RS) - given the Resultset this
will return customer class instance
public static customerinsert1(String fielsName String content) handle
resultset from deifferent operations
public customerinset2(String fieldName int content)
I do insert field by field - when client press tab from Textbox it
inserts or updates the the DB field if content of field changed.
etc.. for delete and update

class DBConnection - methods - perform real queries and updates and
inserts etc.
opendir() - open connection to DB
closedir() -close connection
pquery() - perform query on db

class mywindow - has GUI
then this class will take customer instance and fill the fields
cna pass textfield vlaues to the instace of customer class

any other better way to do this?? I am sure ... yes!!!
Tks for any advice on this matter.

Anil