Inner beans in Spring IOC

Inner beans

Spring IOC allows Inner Beans declaration. We can declare a bean inside a beans. But, it has few restriction. Inner Beans are like annonymous beans where it is created and used on the fly. this beans cannot be used outside the enclosing beans. So, it is wise to avoid declaring the ‘ID‘ or ‘SCOPE‘ attributes for them. Because, these values will be ignored by the container. Only the enclosing beans can access them.

also read:

Employee.java


package javabeat.net.spring.ioc;

/**
 * Source : http://www.javabeat.net
 */

public class Employee {
    private String name;
    private String empId;
    private Address address;
    public Employee(){
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public String getEmpId() {
        return empId;
    }

    public void setEmpId(String empId) {
        this.empId = empId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

Address.java

package javabeat.net.spring.ioc;
/**
 * Source : http://www.javabeat.net
 */

public class Address {
    public Address(){

    }
    private String street;
    private String city;
    private String pincode;

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getPincode() {
        return pincode;
    }

    public void setPincode(String pincode) {
        this.pincode = pincode;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

}

ConstructorInjection.java

package javabeat.net.spring.ioc;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;

/**
 * source : www.javabeat.net
 */
public class ConstructorInjection {
    public static void main(String args[]){
        Resource xmlResource = new FileSystemResource("applicationContext.xml");
        BeanFactory factory = new XmlBeanFactory(xmlResource);
        Employee employee = (Employee)factory.getBean("employeeBean");
        Address address = employee.getAddress();
        System.out.println(employee.getName());
        System.out.println(employee.getEmpId());
        System.out.println(address.getCity());
        System.out.println(address.getStreet());
        System.out.println(address.getPincode());
    }
}

applicationContext.xml


<?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-2.5.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
    <bean id="employeeBean" class="javabeat.net.spring.ioc.Employee">
        <property name="name" value="MyName"/>
        <property name="empId"  value="001"/>
        <property name="address">
            <bean class="javabeat.net.spring.ioc.Address">
                <property name="street">
                    <value>Street</value>
                </property>
                <property name="city">
                    <value>Bangalore</value>
                </property>
                <property name="pincode">
                    <value>567456</value>
                </property>
            </bean>
        </property>
    </bean>
</beans>

also read:

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About Krishna Srinivasan

He is Founder and Chief Editor of JavaBeat. He has more than 8+ years of experience on developing Web applications. He writes about Spring, DOJO, JSF, Hibernate and many other emerging technologies in this blog.

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