Injecting Collections in Spring Application

@ImageSource-SlideShare.net

You have seen how to configure primitive data type using value attribute and object references using ref attribute of the tag in your Bean configuration file(spring.xml). Both the cases deal with passing singular value to a bean. Now we will discuss about passing multiple value of data like List, Set, Collection, Map, Properties etc. To handle the situation, Spring offers four types of collection configuration element.

Popular Tutorials

• Spring Tutorial
• Spring MVC Web Tutorial
• Spring Boot Tutorial
• Spring Security Tutorial
• Spring AOP Tutorial
• Spring JDBC Tutorial
• Spring HATEOAS
• Microservices with Spring Boot
• REST Webservice
• Core Java
• Hibernate Tutorial
• Spring Batch

Injecting Collections in the Spring Application

There are different tags are using by these different Collection elements as follows:

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

Using List

Lets see that code snip sett how to use the List in the spring bean configuration file.

In this code snipset list contain all values tags only.

<property name="listOfShape">
   <list>
      <value>Triangle</value>
      <value>Circle</value>
      <value>Rectangle</value>
      <value>Square</value>
   </list>
</property>

In this code snipset list contain values and beans and inner bean tags.

<property name="listOfShape">
   <list>
      <value>Triangle</value>
      <value>Circle</value>
      <ref bean="rectangle"></ref>      
      <bean class="com.dineshonjava.sdnext.Square">
          <property name="width" value="20"></property>
      </bean>
    </list>
</property>

Using Set

Lets see that code snip sett how to use the Set in the spring bean configuration file.

In this code snipset set contain all values tags only.

<property name="setOfShape">
   <set>
      <value>Triangle</value>
      <value>Circle</value>
      <value>Rectangle</value>
      <value>Square</value>
   </set>
</property>

In this code snipset set contain values and beans and inner bean tags.

<property name="setOfShape">
   <set>
      <value>Triangle</value>
      <value>Circle</value>
      <ref bean="rectangle"></ref>      
      <bean class="com.dineshonjava.sdnext.Square">
          <property name="width" value="20"></property>
      </bean>
   </set>
</property>

Using Map

Lets see that code snip sett how to use the Map in the spring bean configuration file.

In this code snipset mapcontain all values tags only.

<property name="mapOfShape">
   <map>
     <entry key="1" value="Triangle">
     <entry key="2" value="Circle">
     <entry key="3" value="Rectangle">
     <entry key="4" value="Square">
     </entry></entry></entry></entry>
   </map>
</property>

In this code snipset map contain values and beans and inner bean tags.

<property name="mapOfShape">
   <map>
     <entry key="1" value="Triangle"></entry>
     <entry key="2" value="Circle"></entry>
     <entry key="3" value-ref="rectangle"></entry>
     <entry key="4">
        <bean class="com.dineshonjava.sdnext.Square">
          <property name="width" value="20"></property>
        </bean>
     </entry>
   </map>
</property>

Using Properties file

Lets see that code snip sett how to use the Properties file in the spring bean configuration file.

<property name="proprtyOfShape">
   <props>
     <prop key="triangle">Triangle</prop>
     <prop key="circle">Circle</prop>
     <prop key="rectangle">Rectangle</prop>
     <prop key="sqare">Square</prop>
   </props>
</property>

ShapeCollection.java

package com.dineshonjava.sdnext.injectingCollection;

import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

public class ShapeCollection {
 private List<string>        shapeOfList;
 private Set<string>         shapeOfSet;
 private Map<string string=""> shapeOfMap;
 private Properties          shapeOfProperties;
 /**
  * @param shapeOfList the shapeOfList to set
  */
 public void setShapeOfList(List<string> shapeOfList) {
  this.shapeOfList = shapeOfList;
 }
 /**
  * @param shapeOfSet the shapeOfSet to set
  */
 public void setShapeOfSet(Set<string> shapeOfSet) {
  this.shapeOfSet = shapeOfSet;
 }
 /**
  * @param shapeOfMap the shapeOfMap to set
  */
 public void setShapeOfMap(Map<string string=""> shapeOfMap) {
  this.shapeOfMap = shapeOfMap;
 }
 /**
  * @param shapeOfProperties the shapeOfProperties to set
  */
 public void setShapeOfProperties(Properties shapeOfProperties) {
  this.shapeOfProperties = shapeOfProperties;
 }
 
 public String toString()
 {
return "List Elements :"  + shapeOfList+"nSet Elements :"  + shapeOfSet+"n" +
 "Map Elements :"  + shapeOfMap+"nProperty Elements :"  + shapeOfProperties;
  
 }

}

spring.xml

<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemalocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

   
   <bean class="com.dineshonjava.sdnext.injectingCollection.ShapeCollection" id="shapeCollection">

      
      <property name="shapeOfList">
        <list>
           <value>Triangle</value>
           <value>Circle</value>
           <value>Circle</value>
           <value>Rectangle</value>
        </list>
      </property>

     
     <property name="shapeOfSet">
        <set>
           <value>Triangle</value>
           <value>Circle</value>
           <value>Circle</value>
           <value>Rectangle</value>
        </set>
      </property>

     
     <property name="shapeOfMap">
        <map>
           <entry key="1" value="Triangle">
           <entry key="2" value="Circle">
           <entry key="3" value="Circle">
           <entry key="4" value="Rectangle">
        </entry></entry></entry></entry></map>
      </property>

     
     <property name="shapeOfProperties">
        <props>  
      <prop key="triangle">Triangle</prop>  
      <prop key="circle1">Circle</prop>  
      <prop key="circle2">Circle</prop>  
      <prop key="rectangle">Rectangle</prop>  
    </props> 
      </property>

   </bean>

</beans>

DrawingApp.java

package com.dineshonjava.sdnext.injectingCollection.tutorial;

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

import com.dineshonjava.sdnext.injectingCollection.ShapeCollection;


/**
 * @author Dinesh Rajput
 *
 */
public class DrawingApp 
{
 /**
  * @param args
  */
 public static void main(String[] args) 
 {
  ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
  ShapeCollection shapeCollection = (ShapeCollection) context.getBean("shapeCollection");
  System.out.println(shapeCollection);
 }
}