you have to create many redundant codes (create connection , close connection , handle exception) in all the DAO database operation methods – insert, update and delete. It just not efficient, ugly, error prone and tedious.
Example With JdbcTemplate
With JdbcTemplate, you save a lot of typing on the redundant codes, becuase JdbcTemplate will handle it automatically.
Example With JdbcDaoSupport
By extended the JdbcDaoSupport, set the datasource and JdbcTemplate in your class is no longer required, you just need to inject the correct datasource into JdbcCustomerDAO. And you can get the JdbcTemplate by using a getJdbcTemplate() method.
http://www.mkyong.com/spring/spring-jdbctemplate-jdbcdaosupport-examples/
HibernateTemplate and HibernateDaoSupport these classes should be considered deprecated since the release of hibernate 3.0.1
JdbcTemplate (and all other *Template classes) intend is to make it easier to work with the underlying technology. Once upon a time this was also needed for Hibernate (< 3.0.1), now it isn't.
JdbcTemplate makes it easier to work with plain JDBC code. You don't have to get a connection, create a (Prepared)Statement, add the parameters, execute the query, iterate over the resultset and convert the ResultSet. With the JdbcTemplate much of this is hidden and most of it can be written in 1 to 3 lines of code, whereas plain JDBC would require a lot more.
The *Support classes make it easier to gain access to a template but aren't a must to use. Creating a JdbcTemplate is quite easy and you don't really need to extend JdbcDaoSupport. But you can if you want
http://stackoverflow.com/questions/20256787/spring-transaction-of-jdbctemplate-hibernatetemplate-and-hibernatedaosupport-jdb
Spring JDBC DaoSupport
Spring provides convenient classes to perform functions on the database. It handles creating a connection to a database, performing clean up and handling exceptions. The user creates a datasource and injects it into a jdbctemplate. The jdbctemplate is then injected into the spring Dao. The user can also inject a datasource directly into the Dao. The Dao is an abstract class and the user extends this class to create his own Dao. The advantage of this class is that the user does not have to inject the JdbcTemplate into all of his DAO classes. The user creates a common Dao class that can be extended by all the DAO classes. Spring provides two DAO classes JdbcDaoSupport and NamedParameterJdbcDaoSupport. There is a third class called SimpleJdbcDaoSupport but this is now deprecated in favor of JdbcDaoSupport and NamedParameterJdbcDaoSupport
http://www.studytrails.com/frameworks/spring/spring-jdbc-dao-support.jsp
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