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

来源：互联网发布：js仿淘宝选择商品规格编辑：程序博客网时间：2024/05/17 01:36

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

<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/beanshttp://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.