To keep it simple : Use one DAO per entity.
To take advantage of Object oriented programming (ad to have fun !) : Generalise the CRUD ooperations using Abstraction. This way, your DAO class should be able to perform persistent opertaions on any type of entity
Good Luck !
Regards, Sujeeth Pakala
SCJP, SCWCD, SCBCD, ICAD, XML Master Basic, Certified SOA Professional