Spring Dependency Injection
Here we learn what is Dependency Injection and how Spring frame work supports Dependency Injection.
DI is a Jargon created by by Martin Fowler and it is also called as inversion of control. This increases the possibility to reuse these classes and to test them independently of other classes(Unit Testing).In object oriented design, objects have relationship with one another.
A class (A) has a dependency to class (B) if class uses class (B) as a variable.
If dependency injection is used then the class (B) is given to class (A) via
A design based on independent classes / components increases the
re-usability and possibility to test the software. For example if a
class A expects a DAO (Data Access object) for receiving the data from
a database you can easily create another test object which mocks the
database connection and inject this object into A to test A without
having an actual database connection.
A software design based on dependency injection is possible with standard Java.
Process diagram of DI
DI is a Jargon created by by Martin Fowler and it is also called as inversion of control. This increases the possibility to reuse these classes and to test them independently of other classes(Unit Testing).In object oriented design, objects have relationship with one another.
A class (A) has a dependency to class (B) if class uses class (B) as a variable.
If dependency injection is used then the class (B) is given to class (A) via
-
the constructor of the class (A) - this is then called
construction injection
-
a setter - this is then called setter injection
A software design based on dependency injection is possible with standard Java.
Process diagram of DI
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