Spring Annotation and XML Based Configuration

In this topic, we will learn to create a String application and configure it using the XML and annotations code. Let's create a maven project and configure it using the XML file. If you are not familiar with the maven project, then you can read our detailed article here.

The following are the files created in our project. The source code of these files is given below.

• Employee.java

• Accountant.java

• Manager.java

• BankApp.java

• applicationContext.xml

And the following is our project structure after creating all the above files (Java and XML).

Spring Project Structure:

Following is the project structure for the spring project:

Let's create the Java classes and XML files for the project.

BankApp.java

It is a configuration file that reads the applicationContext file and get Bean using the getBean() method and then call method based on the retrieved object.

package com.studytonight.community;

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

public class BankApp {

	private static ApplicationContext context;
	public static void main(String[] args) {

		context = new ClassPathXmlApplicationContext("applicationContext.xml");
		Employee e = (Employee) context.getBean("manager");
		e.doWork();
	}

}

Employee.java

It is an interface that contains an abstract method doWork() which will be overridden by the implemented class.

package com.studytonight.community;

public interface Employee {
	
	void doWork();

}

Accountant.java

It is our bean class that will be used to perform implementations. It implements the Employee interface and implements doWork() method.

package com.studytonight.community;
import org.springframework.stereotype.Component;
@Component
public class Accountant implements Employee{
	
	public void doWork() {
		
		System.out.println("Audit the accounts...");
	}
}

Manager.java

This is another class that implements the Employee interface and override the doWork() method.

package com.studytonight.community;
import org.springframework.stereotype.Component;

@Component
public class Manager implements Employee{
	
	public void doWork() {
		
		System.out.println("Manage the branch office");
	}
}

applicationContext.xml

It is an application context file that configures spring and registers the bean.

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd
                           http://www.springframework.org/schema/context 
                           http://www.springframework.org/schema/context/spring-context.xsd">

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

</beans>

pom.xml

This file contains all the dependencies of this project such as spring jars, servlet jars, etc. Put these dependencies into your project to run the application.

<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.studytonight</groupId>
  <artifactId>springApp</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <dependencies>
		<!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
		<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>
		<dependency>
			<groupId>javax.annotation</groupId>
			<artifactId>javax.annotation-api</artifactId>
			<version>1.3.2</version>
		</dependency>
	</dependencies>
	<properties>
		<spring.version>5.2.8.RELEASE</spring.version>
	</properties>
	<build>
		<sourceDirectory>src</sourceDirectory>
		<plugins>
			<plugin>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.8.1</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
				</configuration>
			</plugin>
		</plugins>

	</build>
</project>

Run the Application:

After successfully completing the project and adding the dependencies run the application and you will get the output as below.

Manage the branch office