Spring Map Element

The map element will create a java.util.Map that can be injected into a constructor or property. The map element expects an entry element inside it to define key/value pairs for the Map.

Following example demonstrates Spring Map Element:

First create a new Java Project and configure it as Maven Project. For Reference, Click Here

Add the following dependencies in pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring</artifactId>
        <version>2.5.6</version>
    </dependency>

</dependencies>

1. POJO

Create Address Class as following.

package com.kruders.bean;

import java.util.Set;

public class Employee {
	private String name;
	private Set<Address> set;
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Set<Address> getSet() {
		return set;
	}
	public void setSet(Set<Address> set) {
		this.set = set;
	}
}

Now create Employee Class as following

package com.kruders.bean;

import java.util.Map;

public class Employee {
	private String name;
	private Map<String,Address> maps;
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Map<String, Address> getMaps() {
		return maps;
	}
	public void setMaps(Map<String, Address> maps) {
		this.maps = maps;
	}
}

2. Configuration

Create Spring-Bean.xml and write the following code

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd">

	<bean id="employee" class="com.kruders.bean.Employee">
	   <property name="name" value="Puneet" />
	   <property name="maps">
       	<map>
           <entry key="1">
           		<bean class="com.kruders.bean.Address">
					<property name="city" value="Delhi" />
					<property name="country" value="India" />
		   		</bean>
		   </entry>
		   <entry key="2">
			   <bean class="com.kruders.bean.Address">
					<property name="city" value="Banglore" />
					<property name="country" value="India" />
			   </bean>
		   </entry>
        </map>
       </property>
   </bean>
</beans>

3. Run Program

Create Main.java class that displays the employee details and run it as Java Application

package com.kruders.core;

import java.util.Map;

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

import com.kruders.bean.Address;
import com.kruders.bean.Employee;

public class Main {
	public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("Spring-Beans.xml");
		
		Employee employee = (Employee) context.getBean("employee");

		System.out.println("Name " + employee.getName());
		System.out.println("\nPrinting Map");
		for(Map.Entry<String, Address> entry : employee.getMaps().entrySet()) {
			System.out.print("City " + entry.getValue().getCity());
			System.out.println(", Country " + entry.getValue().getCountry());
		}
		
	}
}

When you run the above example you’ll get an output like:

Name Puneet
Printing Map
City Delhi, Country India
City Banglore, Country India

The folder structure of the example is shown below in Figure 40.1

Figure 40.1 Figure 40.1

You can download the source code of this example here.

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