Spring examples to show you how to inject values into collections type (List, Set, Map, and Properties). 4 major collection types are supported :

  • List – <list/>
  • Set – <set/>
  • Map – <map/>
  • Properties – <props/>

Spring beans

A Customer object, with four collection properties.

package com.mkyong.common;
 
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
 
public class Customer 
{
	private List<Object> lists;
	private Set<Object> sets;
	private Map<Object, Object> maps;
	private Properties pros;
 
	//...
}

See different code snippets to declare collection in bean configuration file.

1. List example

	<property name="lists">
		<list>
			<value>1</value>
			<ref bean="PersonBean" />
			<bean class="com.mkyong.common.Person">
				<property name="name" value="mkyongList" />
				<property name="address" value="address" />
				<property name="age" value="28" />
			</bean>
		</list>
	</property>

2. Set example

	<property name="sets">
		<set>
			<value>1</value>
			<ref bean="PersonBean" />
			<bean class="com.mkyong.common.Person">
				<property name="name" value="mkyongSet" />
				<property name="address" value="address" />
				<property name="age" value="28" />
			</bean>
		</set>
	</property>

3. Map example

	<property name="maps">
		<map>
			<entry key="Key 1" value="1" />
			<entry key="Key 2" value-ref="PersonBean" />
			<entry key="Key 3">
				<bean class="com.mkyong.common.Person">
					<property name="name" value="mkyongMap" />
					<property name="address" value="address" />
					<property name="age" value="28" />
				</bean>
			</entry>
		</map>
	</property>

4. Properties example

	<property name="pros">
		<props>
			<prop key="admin">[email protected]</prop>
			<prop key="support">[email protected]</prop>
		</props>
	</property>

Full 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.mkyong.common.Customer">
 
		<!-- java.util.List -->
		<property name="lists">
			<list>
				<value>1</value>
				<ref bean="PersonBean" />
				<bean class="com.mkyong.common.Person">
					<property name="name" value="mkyongList" />
					<property name="address" value="address" />
					<property name="age" value="28" />
				</bean>
			</list>
		</property>
 
		<!-- java.util.Set -->
		<property name="sets">
			<set>
				<value>1</value>
				<ref bean="PersonBean" />
				<bean class="com.mkyong.common.Person">
					<property name="name" value="mkyongSet" />
					<property name="address" value="address" />
					<property name="age" value="28" />
				</bean>
			</set>
		</property>
 
		<!-- java.util.Map -->
		<property name="maps">
			<map>
				<entry key="Key 1" value="1" />
				<entry key="Key 2" value-ref="PersonBean" />
				<entry key="Key 3">
					<bean class="com.mkyong.common.Person">
						<property name="name" value="mkyongMap" />
						<property name="address" value="address" />
						<property name="age" value="28" />
					</bean>
				</entry>
			</map>
		</property>
 
		<!-- java.util.Properties -->
		<property name="pros">
			<props>
				<prop key="admin">[email protected]</prop>
				<prop key="support">[email protected]</prop>
			</props>
		</property>
 
	</bean>
 
	<bean id="PersonBean" class="com.mkyong.common.Person">
		<property name="name" value="mkyong1" />
		<property name="address" value="address 1" />
		<property name="age" value="28" />
	</bean>
 
</beans>

Run it…

package com.mkyong.common;
 
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);
 
    }
}

Output

Customer [
 
lists=[
1, 
Person [address=address 1, age=28, name=mkyong1], 
Person [address=address, age=28, name=mkyongList]
], 
 
maps={
key 1=1,
key 2=Person [address=address 1, age=28, name=mkyong1], 
key 3=Person [address=address, age=28, name=mkyongMap]
}, 
 
pros={admin=admin@nospam.com, support=support@nospam.com}, 
 
sets=[
1, 
Person [address=address 1, age=28, name=mkyong1], 
Person [address=address, age=28, name=mkyongSet]]
]

Download Source Code

Download it – Spring-Collection-Example.zip (6 KB)
Tags :
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