Spring Collections (List, Set, Map, and Properties) example

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

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">admin@nospam.com</prop>            <prop key="support">support@nospam.com</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">admin@nospam.com</prop>                <prop key="support">support@nospam.com</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]]]

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