JAVA EE: Spring Auto Component Scan - Annotation Types | Spring Tutorial

Thursday 30 August 2018

Spring Auto Component Scan - Annotation Types | Spring Tutorial | Spring Framework

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Spring Auto Component Scan - Annotation Types | Spring Tutorial | Spring Framework

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>

EmployeeDAO.java

package com.ram.dao;

import org.springframework.stereotype.Repository;

@Repository

public class EmployeeDAO

{

    public void addEmployee()

    {

        System.out.println("inside EmployeeDAO addEmployee()");

    }

}

EmployeeService.java

package com.ram.service;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import com.ram.dao.EmployeeDAO;

@Service

public class EmployeeService

{

    @Autowired

    EmployeeDAO employeeDAO;

    public void addEmployee()

    {

        System.out.println("inside EmployeeService addEmployee()");

        employeeDAO.addEmployee();

    }

    @Override

    public String toString()

    {

        return "EmployeeService [employeeDAO=" + employeeDAO + "]";

    }

}

applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 

    xmlns:context="http://www.springframework.org/schema/context"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

    http://www.springframework.org/schema/beans/spring-beans-4.3.xsd

    http://www.springframework.org/schema/context

    http://www.springframework.org/schema/context/spring-context-4.3.xsd">

    <context:component-scan base-package="com.ram" />

</beans>

App.java

package com.ram.core;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.ram.service.EmployeeService;

public class App

{

    public static void main(String[] args)

    {

        ApplicationContext context = new ClassPathXmlApplicationContext(

                "applicationContext.xml");

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

        EmployeeService employeeService = context.getBean("employeeService",

                EmployeeService.class);

        System.out.println(

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

        System.out.println(employeeService);

        employeeService.addEmployee();

    }

}

Output

Aug 15, 2018 10:55:59 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5b37e0d2: startup date [Wed Aug 15 10:55:59 IST 2018]; root of context hierarchy

Aug 15, 2018 10:55:59 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

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

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

Got employeeService object from the ApplicationContext(Spring Container)

EmployeeService [employeeDAO=com.ram.dao.EmployeeDAO@6483f5ae]

inside EmployeeService addEmployee()

inside EmployeeDAO addEmployee()