What are the different types of IOC (dependency injection)

What are the different types of IOC (dependency injection)

There are three types of dependency injection:

·   Constructor Injection (e.g. Pico container, Spring etc): This will injects the dependency via a constructor.

In the class OutputHelper               IOutputGenerator outputGenerator; 

                        OutputHelper(IOutputGenerator outputGenerator){

                                     this.outputGenerator = outputGenerator;       }

In the xml file <bean id="OutputHelper" class="com.mkyong.output.OutputHelper">

                                     <constructor-arg>

                                                 <bean class="com.mkyong.output.impl.CsvOutputGenerator" />

                                     </constructor-arg>

                        </bean>

·   Setter Injection (e.g. Spring): This is the most popular it will injects the dependency via a setter method.

In the class OutputHelper               IOutputGenerator outputGenerator; 

                        public void setOutputGenerator(IOutputGenerator outputGenerator){

                                    this.outputGenerator = outputGenerator;       }

In the xml file  <bean id="OutputHelper" class="com.mkyong.output.OutputHelper">

                                    <property name="outputGenerator" ref="CsvOutputGenerator" />

                                    </property>

                        </bean>

·   Interface Injection (e.g. Avalon): Injection is done through an interface.

Note: Spring supports only Constructor and Setter Injection