JAVA EE: What is IoC Container in Spring?_V2 | What is Spring IoC Container?

Thursday, 24 May 2018

What is IoC Container in Spring?_V2 | What is Spring IoC Container? | Spring Tutorial

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What is IoC Container in Spring?_V2 | What is Spring IoC Container? | Spring Tutorial

Maven Command.txt

Compile:

mvn clean compile

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>

Employee.java

package com.ram.model;

/**
 * Spring bean
 *
 */

public class Employee

{

    private String name;

    public void setName(String name)

    {

        this.name = name;

    }

    public void employeeDetails()

    {

        System.out.println("Employee Name =  " + name);

    }

}

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="employee" class="com.ram.model.Employee">

        <property name="name" value="Peter" />

    </bean>

</beans>

App.java

package com.ram.core;

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;

import com.ram.model.Employee;

public class App

{

    public static void main(String[] args)

    {

        usingBeanFactory();

        usingApplicationContext();

    }

    private static void usingBeanFactory()

    {

        System.out.println("************* Using BeanFactory ************* ");

        Resource resource = new ClassPathResource("applicationContext.xml");

        BeanFactory factory = new XmlBeanFactory(resource);

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

        Employee employee = (Employee) factory.getBean("employee");

        System.out.println(

                "Got employee object from the BeanFactory(Spring Container)");

        employee.employeeDetails();

    }

    private static void usingApplicationContext()

    {

        System.out.println("\n************* Using ApplicationContext ******* ");

        ApplicationContext context = new ClassPathXmlApplicationContext(

                "applicationContext.xml");

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

        Employee employee = (Employee) context.getBean("employee");

        System.out.println(

                "Got employee object from the ApplicationContext(Spring Container)");

        employee.employeeDetails();

    }

}

Output

************* Using BeanFactory *************

Apr 05, 2018 9:44:21 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

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

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

Got employee object from the BeanFactory(Spring Container)

Employee Name =  Peter

************* Using ApplicationContext *******

Apr 05, 2018 9:44:22 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@26ba2a48: startup date [Thu Apr 05 09:44:22 IST 2018]; root of context hierarchy

Apr 05, 2018 9:44:22 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

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

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

Got employee object from the ApplicationContext(Spring Container)

Employee Name =  Peter