XML configuration Vs Annotations configuration in Spring

How to have a non-XML(annotations) based configuration ?

First lets see an XML based configuration.

Book.java:

package com.heapsteep.model;
public class Book {
	private String bookName;
	public void setBookName(String bookName) {
		this.bookName = bookName;		
	}
	public String getBookName() {
		return bookName;
	}	
}

spring-servlet.xml:

<?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.heapsteep"/>
    <bean id="book" class="com.heapsteep.model.Book" init-method="myPostConstruct"
             destroy-method="myPreDestroy">
      <property name="bookName" value="Mahabharat"/>
    </bean>
    
</beans>

SpringDemo.java:

package com.heapsteep;

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

import com.heapsteep.model.Book;
public class SpringDemo {
	public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("spring-servlet.xml");
		Book book = (Book)context.getBean("book");
		System.out.println("Book Name:"+ book.getBookName());	    
	}
} 

Just right-click on the SpringDemo.java and run as “java application”.
You will get the value from the book object.

Now lets convert the above codes to an non-XML(annotations) based configuration:

Book.java: (No changes)

package com.heapsteep.model;
public class Book {
	private String bookName;
	public void setBookName(String bookName) {
		this.bookName = bookName;		
	}
	public String getBookName() {
		return bookName;
	}	
}

Instead of the servlet-config.xml file we will keep a file – MyConfig.java.(We can remove this file as well and write the same snippet inside the calling file -“SpringDemo_WithoutXML.java” as well):

MyConfig.java:

@Configuration
public class MyConfig {
	@Bean(name="book")
	public Book book() {
		Book book=new Book();
		book.setBookName("Ramayana");
		return book;
	}
}

SpringDemo_WithoutXML.java:

public class SpringDemo_WithoutXML {
	public static void main(String[] args) {
		ApplicationContext context = new AnnotationConfigApplicationContext(MyConfig.class);
		Book book = (Book)context.getBean("book");
		System.out.println("Book Name>>>:"+ book.getBookName());
	}
}

Right-click on the SpringDemo_WithoutXML.java and run as Java application.
You will get the respective value of the book bean.

What is the difference between @Bean and @Component in Spring ?

So guys…. in this tutorial we saw how to configure a bean in xml and do the same without an xml, i.e, by annotations.

Hope you enjoyed the tutorial….