Injecting Objects in Spring -Reference Beans

Injecting Objects in Spring – Reference Beans

We have already seen Setter Injection and Constructor Injection. Now we are going to see an example for reference injection.

When we inject one bean definition into another bean that is known as reference injection

Directory Structure

employee.java

package com.javainfinite;

public class employee {
    
    private String ename;
    private int id;

    public String getEname() {
        return ename;
    }

    public void setEname(String ename) {
        this.ename = ename;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
 
}

employeedependent.java

package com.javainfinite;

public class employeedependent {
    
    employee employee;
    employee employee1;

    public employee getEmployee1() {
        return employee1;
    }

    public void setEmployee1(employee employee1) {
        this.employee1 = employee1;
    }

    public employee getEmployee() {
        return employee;
    }

    public void setEmployee(employee employee) {
        this.employee = employee;
    }
    
    public void display()
    {
        System.out.println("Employee Name: "+employee.getEname()+" ID: "+employee.getId());
        System.out.println("Employee Name: "+employee1.getEname()+" ID: "+employee1.getId());
    }
}

operational.java

package com.javainfinite;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;


public class operational {
    
    public static void main(String args[])
    {
        ApplicationContext ac=new ClassPathXmlApplicationContext("applicationContext.xml");
        employeedependent emp=(employeedependent) ac.getBean("employeedependent");
        emp.display();
    }
    
}

applicationContext.xml

<?xml version='1.0' encoding='UTF-8' ?>
<!-- was: <?xml version="1.0" encoding="UTF-8"?> -->
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">


<bean id="employeedependent" class="com.javainfinite.employeedependent">
    <property name="employee" ref="employee1"/>
    <property name="employee1" ref="employee2"/>
</bean>

<bean id="employee1" class="com.javainfinite.employee">
    <property name="ename" value="Alpha"/>
    <property name="id" value="001"/>
</bean>

<bean id="employee2" class="com.javainfinite.employee">
    <property name="ename" value="Beta"/>
    <property name="id" value="002"/>
</bean>

</beans>

Output