8--deep use of spring--8...1 spring provides DAO support

8.8.1 Spring provides the DAO support.

DAO pattern is a standard Java EE design pattern, the core idea of DAO pattern is that all database accesses are done by DAO component, and DAO component encapsulates the increment, delete, check, change and other atomic operations of database. The business logic component relies on the database atomic operations provided by the DAO component to accomplish the implementation of the system business logic.

There are a number of options for the architecture of Java EE applications, but no matter how the details are transformed, Java EE applications can be broadly divided into the following three tiers.

⊙ presentation layer.

⊙ business Logic layer.

⊙ data Persistence layer.

The lightweight Java EE architecture is centered on the spring IOC container, connecting the actions from the presentation layer up, managing the business logic layer components down, and managing the DAO objects required by the business logic layer.

DAO components are an important component of persistent layer access for the entire Java EE application, and the underlying implementation of each Java EE application is difficult to leave behind the support of the DAO component. Spring provides a number of tool classes for implementing DAO components, and DAO components of the system can be accomplished by inheriting these tool classes, making it easier to implement DAO components.

Spring provides a series of abstract classes that will be used as the parent class of the DAO implementation class in the application. By inheriting these abstract classes, spring simplifies the development steps of DAO and can use data access technology in a consistent manner. Consistent programming models can be used in applications, whether JDBC, JDO or hibernate are used in the underlying.

8--deep use of spring--8...1 spring provides DAO support