Nested Beans

Nested Beans

In this tutorial, we are going to discuss nested beans in the spring framework. Declaring a bean configuration in another bean configuration is called Inner Beans or Nested Beans.

In the Bean class, if we declare any property of the User-defined class type, we have to use the tag for the user-defined class as value to the respective property under <property> tag.

Example

package com.ashok.spring.core.bean.nested.beans;

/**
 * 
 * @author Ashok Kumar
 *
 */
public class Account {
   private String accNo;
   private String accName;
   private String accType;
   private long balance;

   public String getAccNo() {
      return accNo;
   }

   public void setAccNo(String accNo) {
      this.accNo = accNo;
   }

   public String getAccName() {
      return accName;
   }

   public void setAccName(String accName) {
      this.accName = accName;
   }

   public String getAccType() {
      return accType;
   }

   public void setAccType(String accType) {
      this.accType = accType;
   }

   public long getBalance() {
      return balance;
   }

   public void setBalance(long balance) {
      this.balance = balance;
   }

   @Override
   public String toString() {
      return "Account [accNo=" + accNo + ", accName=" + accName + ", accType=" + accType + ", balance=" + balance
            + "]";
   }
}

package com.ashok.spring.core.bean.nested.beans;

/**
 * 
 * @author Ashok Kumar
 *
 */
public class Employee {
   private String empName;
   private String empId;
   private String empAddress;
   private Account account;

   public String getEmpName() {
      return empName;
   }

   public void setEmpName(String empName) {
      this.empName = empName;
   }

   public String getEmpId() {
      return empId;
   }

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

   public String getEmpAddress() {
      return empAddress;
   }

   public void setEmpAddress(String empAddress) {
      this.empAddress = empAddress;
   }
   
   public Account getAccount() {
      return account;
   }

   public void setAccount(Account account) {
      this.account = account;
   }

   @Override
   public String toString() {
      return "Employee [empName=" + empName + ", empId=" + empId + ", empAddress=" + empAddress + ", account="
            + account + "]";
   }
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    <bean id="emp"
        class="com.ashok.spring.core.bean.nested.beans.Employee"
        scope="prototype">
        <property name="empName" value="Ashok Kumar" />
        <property name="empId" value="Emp0087" />
        <property name="empAddress" value="Bhimavaram" />
        <property name="account">
            <bean id="acc"
                class="com.ashok.spring.core.bean.nested.beans.Account">
                <property name="accNo" value="123456789" />
                <property name="accName" value="M V Ashok Kumar" />
                <property name="accType" value="Savings" />
                <property name="balance" value="2500" />
            </bean>
        </property>
    </bean>
</beans>

package com.ashok.spring.core.bean.nested.test;

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

import com.ashok.spring.core.bean.nested.beans.Employee;

/**
 * 
 * @author Ashok Kumar
 *
 */
public class TestSpringApplication {
   @SuppressWarnings("resource")
   public static void main(String[] args) {
      String configFile = "/com/ashok/spring/core/bean/nested/config/applicationContext.xml";
      ApplicationContext context = new ClassPathXmlApplicationContext(configFile);
      Employee emp = (Employee) context.getBean("emp");
      System.out.println(emp);
   }
}

Output

Employee [empName=Ashok Kumar, empId=Emp0087, empAddress=Bhimavaram, account=Account [accNo=123456789, accName=M V Ashok Kumar, accType=Savings, balance=2500]]