Constructor Injection DI

Constructor-based DI is effected by invoking a constructor with a number of arguments, each representing a dependency.

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public class ExampleBean {

private AnotherBean beanOne;

private YetAnotherBean beanTwo;

private int i;

public ExampleBean(

AnotherBean anotherBean, YetAnotherBean yetAnotherBean, int i) {

this.beanOne = anotherBean;

this.beanTwo = yetAnotherBean;

this.i = i;

}

}


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<bean id="exampleBean" class="examples.ExampleBean">

<!-- constructor injection using the nested <ref/> element -->

<constructor-arg><ref bean="anotherExampleBean"/>

</constructor-arg><!-- constructor injection using the neater 'ref' attribute -->

<constructor-arg ref="yetAnotherBean"/><constructor-arg type="int" value="1"/></bean>

<bean id="anotherExampleBean" class="examples.AnotherBean"/>

<bean id="yetAnotherBean" class="examples.YetAnotherBean"/>


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