Spring Auto Scanning Components | Spring Component Scan | Spring Tutorial

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Spring Auto Scanning Components | Spring Component Scan | Spring Tutorial

Spring Auto Scanning Components | Spring Component Scan | Spring Tutorial

Spring Auto Scanning Components | Spring Component Scan | Spring Tutorial

Spring Auto Scanning Components | Spring Component Scan | Spring Tutorial

Spring Auto Scanning Components | Spring Component Scan | Spring Tutorial

Spring Auto Scanning Components | Spring Component Scan | Spring Tutorial

            Declares Components Manually

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;

public class EmployeeDAO
{
    public void addEmployee()
    {
        System.out.println("inside EmployeeDAO addEmployee()");
    }

}

EmployeeService.java

package com.ram.service;

import com.ram.dao.EmployeeDAO;

public class EmployeeService
{
    EmployeeDAO employeeDAO;

    public void setEmployeeDAO(EmployeeDAO employeeDAO)
    {
        this.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">

    <bean id="employeeService" class="com.ram.service.EmployeeService">
        <property name="employeeDAO" ref="employeeDAO" />
    </bean>

    <bean id="employeeDAO" class="com.ram.dao.EmployeeDAO" />

</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 14, 2018 9:36:02 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5b37e0d2: startup date [Tue Aug 14 09:36:02 IST 2018]; root of context hierarchy
Aug 14, 2018 9:36:02 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@1794d431]
inside EmployeeService addEmployee()
inside EmployeeDAO addEmployee()

                 Auto Components Scanning

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.Component;

@Component
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.Component;

import com.ram.dao.EmployeeDAO;

@Component
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 14, 2018 9:58:25 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5b37e0d2: startup date [Tue Aug 14 09:58:25 IST 2018]; root of context hierarchy
Aug 14, 2018 9:58:25 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@16022d9d]
inside EmployeeService addEmployee()
inside EmployeeDAO addEmployee()

Click the below link to download the code:
https://sites.google.com/site/ramj2eev2/java_basics/SpringDemo_AutoScaning.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/javaee/tree/master/Spring_2018/SpringDemo_AutoScaning

Bitbucket Link:
https://bitbucket.org/ramram43210/spring/src/d89cccdb22c06b2e0a9adbdbd2c6a120a0f41423/Spring_2018/SpringDemo_AutoScaning/?at=master

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