Spring ListFactoryBean example

The ‘ListFactoryBean‘ class provides developer a way to create a concrete List collection class (ArrayList and LinkedList) in Spring’s bean configuration file.

Here’s a ListFactoryBean example, it will instantiate an ArrayList at runtime, and inject it into a bean property.

package com.tuts.heomi.netmon;

import java.util.List;

public class Customer 
{
	private List lists;
	//...
}

Spring’s bean configuration file.

<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-2.5.xsd">

	<bean id="CustomerBean" class="com.tuts.heomi.netmon.Customer">
		<property name="lists">
			<bean class="org.springframework.beans.factory.config.ListFactoryBean">
				<property name="targetListClass">
					<value>java.util.ArrayList</value>
				</property>
				<property name="sourceList">
					<list>
						<value>1</value>
						<value>2</value>
						<value>3</value>
					</list>
				</property>
			</bean>
		</property>
	</bean>

</beans>

Alternatively, you also can use util schema and <util:list> to achieve the same thing.

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
	http://www.springframework.org/schema/util
	http://www.springframework.org/schema/util/spring-util-2.5.xsd">

	<bean id="CustomerBean" class="com.tuts.heomi.netmon.Customer">
		<property name="lists">
			<util:list list-class="java.util.ArrayList">
				<value>1</value>
				<value>2</value>
				<value>3</value>
			</util:list>
		</property>
	</bean>

</beans>

Remember to include the util schema, else you will hit the following error

Caused by: org.xml.sax.SAXParseException: 
	The prefix "util" for element "util:list" is not bound.

Run it…

package com.tuts.heomi.netmon;

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

public class App {
	public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext(
				"SpringBeans.xml");

		Customer cust = (Customer) context.getBean("CustomerBean");
		System.out.println(cust);
		
	}
}

Ouput

Customer [lists=[1, 2, 3]] Type=[class java.util.ArrayList]

You have instantiated ArrayList and injected it into Customer’s lists property at runtime.

Download Source Code

$ git clone https://github.com/favtuts/java-spring-tutorials.git
$ cd SpringBeanListFactory

Reference

1. ListFactoryBean Javadoc