Spring(6)-Spring Collections (List, Set, Map, and Properties) example

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

By
mkyong - March 14, 2010 spring

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
[code]	
<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]]
]

SpringCollectionExample

Spring ListFactoryBean example

By mkyong - March 15, 2010 spring

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.mkyong.common;

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.mkyong.common.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.mkyong.common.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.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);

}

}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.

Spring SetFactoryBean example

By mkyong - March 16, 2010 spring

The ‘SetFactoryBean‘ class provides developer a way to create a concrete Set collection (HashSet and TreeSet) in Spring’s bean configuration file.

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

package com.mkyong.common;

import java.util.Set;

public class Customer

{

private Set sets;

//...

}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">

<property name="sets">

<bean class="org.springframework.beans.factory.config.SetFactoryBean">

<property name="targetSetClass">

<value>java.util.HashSet</value>

</property>

<property name="sourceSet">

<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:set> 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.mkyong.common.Customer">

<property name="sets">

<util:set set-class="java.util.HashSet">

<value>1</value>

<value>2</value>

<value>3</value>

</util:set>

</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:set" is not bound.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);

}

}Ouput

Customer [sets=[3, 2, 1]] Type=[class java.util.HashSet]You have instantiated HashSet and and injected it into Customer’s sets property at runtime.

Spring MapFactoryBean example

By mkyong - March 17, 2010 spring

The ‘MapFactoryBean‘ class provides developer a way to create a concrete Map collection class (HashMap and TreeMap) in Spring’s bean configuration file.

Here’s a MapFactoryBean example, it will instantiate a HashMap at runtime,, and inject it into a bean property.

package com.mkyong.common;

import java.util.Map;

public class Customer

{

private Map maps;

//...

}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">

<property name="maps">

<bean class="org.springframework.beans.factory.config.MapFactoryBean">

<property name="targetMapClass">

<value>java.util.HashMap</value>

</property>

<property name="sourceMap">

<map>

<entry key="Key1" value="1" />

<entry key="Key2" value="2" />

<entry key="Key3" value="3" />

</map>

</property>

</bean>

</property>

</bean>

</beans>Alternatively, you also can use util schema and <util:map> 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.mkyong.common.Customer">

<property name="maps">

<util:map map-class="java.util.HashMap">

<entry key="Key1" value="1" />

<entry key="Key2" value="2" />

<entry key="Key3" value="3" />

</util:map>

</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:map" is not bound.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);

}

}Ouput

Customer [maps={Key2=2, Key1=1, Key3=3}] Type=[class java.util.HashMap]You have instantiated a HashMap and injected it into Customer’s map property at runtime.