Setter Dependency Injection with List of Integer/Long example

In some scenarios, we may need to inject a list of Integers/Long to an object rather than just one Integer/Long value.

Consider the example where one Person has multiple phone numbers

In this case, we are required to inject list of Long object to person object.

Let us see the same in spring through Setter Dependency Injection

Create a class called Person

It contains 3 attributes id,name and phoneNumbers where phoneNumbers is a list of Long

It contains 3 setter methods one for each attribute.

It also contains showPersonPhoneNumbers() method to display the list of phoneNumbers that we have injected to the person object.

  1. package com.kb.di;
  2.  
  3. import java.util.List;
  4.  
  5. public class Person {
  6.     private int id;
  7.     private String name;
  8.     private List<Long> phoneNumbers;
  9.    
  10.     public void showPersonPhoneNumbers() {
  11.         for (Long phoneNumber : phoneNumbers) {
  12.             System.out.println(phoneNumber);
  13.         }
  14.     }
  15.  
  16.     public void setId(int id) {
  17.         this.id = id;
  18.     }
  19.  
  20.     public void setName(String name) {
  21.         this.name = name;
  22.     }
  23.  
  24.     public void setPhoneNumbers(List<Long> phoneNumbers) {
  25.         this.phoneNumbers = phoneNumbers;
  26.     }
  27. }
package com.kb.di;

import java.util.List;

public class Person {
	private int id;
	private String name;
	private List<Long> phoneNumbers;
	
	public void showPersonPhoneNumbers() {
		for (Long phoneNumber : phoneNumbers) {
			System.out.println(phoneNumber);
		}
	}

	public void setId(int id) {
		this.id = id;
	}

	public void setName(String name) {
		this.name = name;
	}

	public void setPhoneNumbers(List<Long> phoneNumbers) {
		this.phoneNumbers = phoneNumbers;
	}
}

Create a spring bean definition file

In this file, we used < property > tag with < list > to define the list of Long.

< value > tag is used to inject the values

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <beans xmlns="http://www.springframework.org/schema/beans"
  3.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
  4.     xsi:schemaLocation="http://www.springframework.org/schema/beans
  5.        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
  6.  
  7.  
  8.     <bean id="person" class="com.kb.di.Person">
  9.         <property name="id" value="1"></property>
  10.         <property name="name" value="Raj"></property>
  11.         <property name="phoneNumbers">
  12.             <list>
  13.                 <value>9999912345</value>
  14.                 <value>9999956789</value>
  15.  
  16.             </list>
  17.         </property>
  18.  
  19.     </bean>
  20. </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">


	<bean id="person" class="com.kb.di.Person">
		<property name="id" value="1"></property>
		<property name="name" value="Raj"></property>
		<property name="phoneNumbers">
			<list>
				<value>9999912345</value>
				<value>9999956789</value>

			</list>
		</property>

	</bean>
</beans>

Create a pom.xml file

  1. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  2.   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  3.   <modelVersion>4.0.0</modelVersion>
  4.  
  5.   <groupId>Spring</groupId>
  6.   <artifactId>SpringCore</artifactId>
  7.   <version>0.0.1-SNAPSHOT</version>
  8.   <packaging>jar</packaging>
  9.  
  10.   <name>SpringCore</name>
  11.   <url>http://maven.apache.org</url>
  12.  
  13.   <properties>
  14.     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  15.   </properties>
  16.  
  17.   <dependencies>
  18.   <dependency>
  19.     <groupId>org.springframework</groupId>
  20.     <artifactId>spring-core</artifactId>
  21.     <version>4.2.4.RELEASE</version>
  22. </dependency>
  23.   <dependency>
  24.     <groupId>org.springframework</groupId>
  25.     <artifactId>spring-context</artifactId>
  26.     <version>4.2.4.RELEASE</version>
  27. </dependency>
  28.  
  29.     <dependency>
  30.       <groupId>junit</groupId>
  31.       <artifactId>junit</artifactId>
  32.       <version>3.8.1</version>
  33.       <scope>test</scope>
  34.     </dependency>
  35.   </dependencies>
  36. </project>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>Spring</groupId>
  <artifactId>SpringCore</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>SpringCore</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
  <dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-core</artifactId>
	<version>4.2.4.RELEASE</version>
</dependency>
  <dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-context</artifactId>
	<version>4.2.4.RELEASE</version>
</dependency>
  
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

Create a SetterDI class

This class loads the spring beans using application context and calls the person class method to display the list of phone numbers.

  1. package com.kb.di;
  2.  
  3. import org.springframework.beans.factory.BeanFactory;
  4. import org.springframework.beans.factory.xml.XmlBeanFactory;
  5. import org.springframework.context.ApplicationContext;
  6. import org.springframework.context.support.ClassPathXmlApplicationContext;
  7. import org.springframework.core.io.ClassPathResource;
  8. import org.springframework.core.io.Resource;
  9.  
  10. public class SetterDI  {
  11.    
  12.     public static void main(String[] args) {
  13.         ApplicationContext applicationContext=new ClassPathXmlApplicationContext("beans.xml");  
  14.         Person person = (Person)applicationContext.getBean("person");
  15.         person.showPersonPhoneNumbers();
  16.    
  17.        
  18.     }
  19.  
  20. }
package com.kb.di;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;

public class SetterDI  {
	
	public static void main(String[] args) {
        ApplicationContext applicationContext=new ClassPathXmlApplicationContext("beans.xml");  
        Person person = (Person)applicationContext.getBean("person");
        person.showPersonPhoneNumbers();
    
        
	}

}

Run the SetterDI class and see the output as below

same can be achieved for Integers just by changing Long to Integer in Person class.

About the Author

Raj
Founder of javainsimpleway.com
I love Java and open source technologies and very much passionate about software development.
I like to share my knowledge with others especially on technology 🙂
I have given all the examples as simple as possible to understand for the beginners.
All the code posted on my blog is developed,compiled and tested in my development environment.
If you find any mistakes or bugs, Please drop an email to kb.knowledge.sharing@gmail.com

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