JAVA EE: How to Inject Map having dependent Object in key and value using dependency injection by constructor

Friday, 1 June 2018

How to Inject Map having dependent Object in key and value using dependency injection by constructor

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How to Inject Map having dependent Object in key and value using dependency injection by constructor

pom.xml

<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%20http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.ram.core</groupId>

    <artifactId>SpringDemo</artifactId>

    <packaging>jar</packaging>

    <version>1.0-SNAPSHOT</version>

    <name>SpringDemo</name>

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

    <properties>

        <spring.version>5.0.2.RELEASE</spring.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>3.8.1</version>

            <scope>test</scope>

        </dependency>

        <!-- Spring 5 dependencies -->

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-core</artifactId>

            <version>${spring.version}</version>

        </dependency>

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-context</artifactId>

            <version>${spring.version}</version>

        </dependency>

    </dependencies>

</project>

FruitSeller.java

package com.ram.model;

public class FruitSeller

{

    private String name;

    private String emailId;

    public FruitSeller(String name, String emailId)

    {

        System.out.println("FruitSeller(String name, String emailId) "

                + "constructor is called by the Spring container");

        this.name = name;

        this.emailId = emailId;

    }

    @Override

    public String toString()

    {

        return "FruitSeller [name=" + name + ", emailId=" + emailId + "]";

    }

}

Fruit.java

package com.ram.model;

public class Fruit

{

    private String name;

    private String color;

    public Fruit(String name, String color)

    {

        System.out.println("Fruit(String name, String color) "

                + "constructor is called by the Spring container");

        this.name = name;

        this.color = color;

    }

    @Override

    public String toString()

    {

        return "Fruit [name=" + name + ", color=" + color + "]";

    }

}

FruitInfo.java

package com.ram.core;

import java.util.Iterator;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Set;

import com.ram.model.Fruit;

import com.ram.model.FruitSeller;

public class FruitInfo

{

    private Map<FruitSeller, Fruit> mapOfFruitSellerAndFruit;

    public FruitInfo(Map<FruitSeller, Fruit> mapOfFruitSellerAndFruit)

    {

        System.out.println(

                "FruitInfo(Map<FruitSeller, Fruit> mapOfFruitSellerAndFruit) "

                        + "constructor is called by the Spring container");

        this.mapOfFruitSellerAndFruit = mapOfFruitSellerAndFruit;

    }

    public void displayFruitInfo()

    {

        System.out.println("FruitInfo [mapOfFruitSellerAndFruit="

                + mapOfFruitSellerAndFruit + "]");

        Set<Entry<FruitSeller, Fruit>> set = mapOfFruitSellerAndFruit

                .entrySet();

        Iterator<Entry<FruitSeller, Fruit>> itr = set.iterator();

        while (itr.hasNext())

        {

            Entry<FruitSeller, Fruit> entry = itr.next();

            System.out.println("FruitSeller = " + entry.getKey() + ", Fruit = "

                    + entry.getValue());

        }

    }

}

applicationContext.xml

<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-4.3.xsd">

    <bean id="fruitSeller1" class="com.ram.model.FruitSeller">

        <constructor-arg type="String" value="Peter"></constructor-arg>

        <constructor-arg type="String" value="Peter@yahoo.com"></constructor-arg>

    </bean>

    <bean id="fruitSeller2" class="com.ram.model.FruitSeller">

        <constructor-arg type="String" value="John"></constructor-arg>

        <constructor-arg type="String" value="John@gmail.com"></constructor-arg>

    </bean>

    <bean id="fruit1" class="com.ram.model.Fruit">

        <constructor-arg type="String" value="Apple"></constructor-arg>

        <constructor-arg type="String" value="Red"></constructor-arg>

    </bean>

    <bean id="fruit2" class="com.ram.model.Fruit">

        <constructor-arg type="String" value="Grapes"></constructor-arg>

        <constructor-arg type="String" value="Violet"></constructor-arg>

    </bean>

    <bean id="fruitInfo" class="com.ram.core.FruitInfo">

        <constructor-arg type="java.util.Map">

            <map>

                <entry key-ref="fruitSeller1" value-ref="fruit1"></entry>

                <entry key-ref="fruitSeller2" value-ref="fruit2"></entry>

            </map>

        </constructor-arg>

    </bean>

</beans>

App.java

package com.ram.core;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App

{

    public static void main(String[] args)

    {

        ApplicationContext context = new ClassPathXmlApplicationContext(

                "applicationContext.xml");

        System.out.println("---------------------------------------");

        FruitInfo fruitShop = (FruitInfo) context.getBean("fruitInfo");

        System.out.println(

                "Got fruitInfo object from the ApplicationContext(Spring container)");

        fruitShop.displayFruitInfo();

    }

}

Output

Apr 30, 2018 9:47:13 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5b37e0d2: startup date [Mon Apr 30 09:47:13 IST 2018]; root of context hierarchy

Apr 30, 2018 9:47:13 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

INFO: Loading XML bean definitions from class path resource [applicationContext.xml]

FruitSeller(String name, String emailId) constructor is called by the Spring container

FruitSeller(String name, String emailId) constructor is called by the Spring container

Fruit(String name, String color) constructor is called by the Spring container

Fruit(String name, String color) constructor is called by the Spring container

FruitInfo(Map<FruitSeller, Fruit> mapOfFruitSellerAndFruit) constructor is called by the Spring container

---------------------------------------

Got fruitInfo object from the ApplicationContext(Spring container)

FruitInfo [mapOfFruitSellerAndFruit={FruitSeller [name=Peter, emailId=Peter@yahoo.com]=Fruit [name=Apple, color=Red], FruitSeller [name=John, emailId=John@gmail.com]=Fruit [name=Grapes, color=Violet]}]

FruitSeller = FruitSeller [name=Peter, emailId=Peter@yahoo.com], Fruit = Fruit [name=Apple, color=Red]

FruitSeller = FruitSeller [name=John, emailId=John@gmail.com], Fruit = Fruit [name=Grapes, color=Violet]