Dependency Injection JAVA EE - Spring Framework

Inner Beans As you know Java inner classes are defined within the scope of other classes, similarly, inner beans are beans that are defined within the scope of another bean. Thus, a element inside the or elements is called inner bean.

Example: My aim is to create an application where I can add users into database. Step 1: Use hibernate library for database connection and manipulation Step 2: Create bean called DBConnect for database connection Step 3: Use DBConnect bean inside of UserBean

DBConnect.java class

hibernate.cfg.xml configuration XML file

UserBean.java class

applicationContext.xml configuration XML file

AddUser Servlet class

Injecting Collection You have seen how to configure primitive data type using value attribute and object references using ref attribute of the tag in your Bean configuration file. Both the cases deal with passing singular value to a bean.

Types of collection configuration elements ElementDescription This helps in wiring ie injecting a list of values, allowing duplicates. This helps in wiring a set of values but without any duplicates. This can be used to inject a collection of name- value pairs where name and value can be of any type. This can be used to inject a collection of name- value pairs where the name and value are both Strings.

Example:

Bean injection

Beans.xml

Developing Project with using inheritance In project Development we should use inherit beans from parent beans. We can create an ApplicationBean class, where I have property of DBConnect bean. All my beans will be inherited from ApplicationBean class.

ApplicationBean.java bean class

UserBean class is inherited from ApplicationBean

applicationContext.xml

Thank you for attention