Basics of Spring Framework

 This spring tutorial provides in-depth concepts of Spring Framework with simplified examples. It was developed by Rod Johnson in 2003. Spring framework makes the easy development of the JavaEE application.

Spring Framework

Spring is a lightweight framework. It can be thought of as a framework of frameworks because it provides support to various frameworks such as Struts, Hibernate, Tapestry, EJB, JSF, etc. The framework, in a broader sense, can be defined as a structure where we find solutions of various technical problems.

The Spring framework comprises several modules such as IOC, AOP, DAO, Context, ORM, WEB MVC, etc. We will learn these modules on the next page. Let's understand the IOC and Dependency Injection first.

Inversion Of Control (IOC) and Dependency Injection

These are the design patterns that are used to remove dependency from the programming code. They make the code easier to test and maintain. Let's understand this with the following code:

class Employee{  

Address address;  

Employee(){  

address=new Address();  

}  

}  

In such a case, there is the dependency between the Employee and Address (tight coupling). In the Inversion of Control scenario, we do this something like this:

class Employee{  

Address address;  

Employee(Address address){  

this.address=address;  

}  

}  

Thus, IOC makes the code loosely coupled. In such a case, there is no need to modify the code if our logic is moved to a new environment.

In the Spring framework, the IOC container is responsible to inject the dependency. We provide metadata to the IOC container either by XML file or annotation.

Advantage of Dependency Injection:

makes the code loosely coupled so easy to maintain

makes the code easy to test

Advantages of Spring Framework:

There are many advantages of the Spring Framework. They are as follows:

1) Predefined Templates-

Spring framework provides templates for JDBC, Hibernate, JPA, etc. technologies. So there is no need to write too much code. It hides the basic steps of these technologies.

Let's take the example of JdbcTemplate, you don't need to write the code for exception handling, creating connections, creating statements, committing transactions, closing connections, etc. You need to write the code for executing the query only. Thus, it saves a lot of JDBC code.

2) Loose Coupling-

The Spring applications are loosely coupled because of dependency injection.

3) Easy to test-

The Dependency Injection makes it easier to test the application. The EJB or Struts application requires the server to run the application but the Spring framework doesn't require a server.

4) Lightweight-

Spring framework is lightweight because of its POJO implementation. The Spring Framework doesn't force the programmer to inherit any class or implement any interface. That is why it is said non-invasive.

5) Fast Development-

The Dependency Injection feature of Spring Framework and it support to various frameworks make the easy development of the JavaEE application.

6) Powerful abstraction-

It provides a powerful abstraction to JavaEE specifications such as JMS, JDBC, JPA, and JTA.

7) Declarative support-

It provides declarative support for caching, validation, transactions, and formatting.