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Chapter 4. Data Access with Spring


If you are using transactions in your application, you will inevitably also be accessing some persistent resources. Spring provides a variety of APIs to support programmatic access to persistent resources and you might find it helpful to familiarize yourself with these data access APIs. In particular, this chapter describes Spring's JDBC API in some detail.

4.1. Programming Data Access with Spring Templates


To provide access to various kinds of persistent storage, Spring encapsulates the relevant API in a template class. The purpose of the template class is to provide a simplifying wrapper layer around each type of storage and to ensure that any required Spring features are integrated cleanly with the persistence layer.
Spring provides the following template classes for data access:

JmsTemplate class

The org.springframework.jms.core.JmsTemplate class is a general-purpose class for managing Java Messaging Service (JMS) connections. One of the main advantages of this class is that it simplifies the JMS synchronous access codes.
To create an instance of a JmsTemplate, you need to supply a reference to a javax.jms.ConnectionFactory object.

JdbcTemplate class

The org.springframework.jdbc.core.JdbcTemplate class is a wrapper around a JDBC data source, enabling you to access a JDBC database using SQL operations.
To create an instance of a JdbcTemplate, you need to supply a reference to a javax.sql.DataSource object (for example, see Section 2.6.1, “JDBC Data Source”).
For a detailed discussion of the JdbcTemplate class, see Section 4.2, “Spring JDBC Template”.

SimpleJdbcTemplate class

The org.springframework.jdbc.core.simple.SimpleJdbcTemplate class is a convenience wrapper around the JdbcTemplate class. This class has been pared down so that it includes only the most commonly used template methods and it has been optimized to exploit Java 5 features.

NamedParameterJdbcTemplate class

The org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate class is a convenience wrapper around the JdbcTemplate class, which enables you to use named parameters instead of the usual ? placeholders embedded in a SQL statement.

SqlMapClientTemplate class

The org.springframework.orm.ibatis.SqlMapClientTemplate class is a simplifying wrapper around the iBATIS SqlMapClient class. iBATIS is an Object Relational Mapper (ORM) that is capable of automatically instantiating Java objects based on a given SQL database schema.

HibernateTemplate class

The org.springframework.orm.hibernate3.HibernateTemplate class provides an alternative to working with the raw Hibernate 3 session API (based on sessions returned from SessionFactory.getCurrentSession()).
For Hibernate versions 3.0.1 or later, the Spring documentation recommends that you use the native Hibernate 3 API instead of the HibernateTemplate class, because transactional Hibernate access code can now be coded using the native Hibernate API.

JdoTemplate class

The org.springframework.orm.jdo.JdoTemplate class provides an alternative to working with the raw JDO PersistenceManager API. The main difference between the APIs relates to their exception handling. See the Spring JavaDoc for details.

JpaTemplate class

The org.springframework.orm.jpa.JpaTemplate class provides an alternative to working with the raw JPA EntityManager API..
The Spring documentation now recommends that you use the native JPA programming interface instead of the JpaTemplate class. Considering that the JPA programming interface is itself a thin wrapper layer, there is little advantage to be had by adding another wrapper layer on top of it.