Spring is a robust, lightweight framework for Java that is used to create enterprise-level applications. It offers complete infrastructure support so that creating reliable apps is simple. Learn Spring Boot from scratch with this comprehensive tutorial. Explore the best Spring Boot course syllabus to kickstart your Java app development journey.
Getting Started with Spring Boot
You will need the following to begin using Spring:
- Java Development Kit (JDK): JDK 8 or later is required for Spring.
- Build Tool: To manage dependencies, use Gradle or Maven.
- IDE: Make use of an IDE such as Visual Studio Code, Eclipse, or IntelliJ IDEA.
Maven Dependency
Add the following dependency in your Spring Core pom.xml file:
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>6.0.0</version> <!– Use the latest version –>
</dependency>
Recommended: Spring Boot Online Course Program.
Spring Core Concepts
The Spring Framework is built on top of Spring Core, which offers essential capabilities and building blocks for creating reliable Java applications. Here are some essential concepts:
Inversion of Control (IoC)
- Traditional Approach: Objects in traditional programming are in charge of establishing and maintaining their own dependencies.
- IoC: IoC transfers the burden of object creation and management to an external entity, usually the Spring container. This encourages loose coupling and increases the adaptability and testability of applications.
Dependency Injection (DI)
- A form of IoC: One type of IoC is DI, a design pattern in which a class does not create its own dependents (other objects); rather, the Spring container injects them into the class.
- Types of DI:
- Constructor Injection: The class’s constructor is used to supply dependencies.
- Setter Injection: Setter methods are used to set dependencies.
- Field Injection: The @Autowired annotation is used to directly inject dependencies into fields.
Spring Container
- Core of Spring: In a Spring application, the Spring container is in charge of generating, setting up, and overseeing the lifetime of objects, or beans.
- Container Types:
- BeanFactory: The fundamental interface for gaining access to configured beans is called BeanFactory.
- ApplicationContext: A BeanFactory extension that offers extra functionality including resource loading, internationalization, and event posting.
Beans
- Managed Objects: The Spring container is in charge of managing beans.
- Configuration: Annotations or XML or Java-based configuration files are used to define beans.
- Lifecycle: The creation, initialization, and disposal of beans are all managed by the Spring container.
Spring Annotations
- Simplified Configuration: Beans and their dependencies can be configured succinctly with annotations.
- Typical Annotations:
- @Service, @Component, and @Repository: Designate classes as Spring beans.
- @Autowired: Dependencies are wired automatically.
- @Qualifier: When there are several beans of the same kind available, choose which one to inject.
Review your core skills with our Java interview questions and answers.
Creating a Simple Spring Application
Step 1: Define a Bean
Create a simple Java class:
public class HelloWorld {
private String message;
public void setMessage(String message) {
this.message = message;
}
public void getMessage() {
System.out.println(“Your Message: ” + message);
}
}
Step 2: Use Spring Configuration to set up the bean
To define the bean, create a configuration file called beans.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.xsd”>
<bean id=”helloWorld” class=”com.example.HelloWorld”>
<property name=”message” value=”Hello, Spring!”/>
</bean>
</beans>
Step 3: Use the Bean and Load the Spring Context
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class MainApp {
public static void main(String[] args) {
// Load the Spring configuration file
ApplicationContext context = new ClassPathXmlApplicationContext(“beans.xml”);
// Retrieve the bean
HelloWorld helloWorld = (HelloWorld) context.getBean(“helloWorld”);
// Use the bean
helloWorld.getMessage();
}
}
Suggested: Java Course in Chennai.
Spring Annotations
For dependency injection and bean configuration, annotations can be used in place of XML configuration.
Activate Configuration Based on Annotations
The following should be added to your configuration file:
<context:annotation-config/>
<context:component-scan base-package=”com.example”/>
Example:
import org.springframework.stereotype.Component;
import org.springframework.beans.factory.annotation.Autowired;
@Component
public class HelloWorld {
private String message;
@Autowired
public void setMessage(String message) {
this.message = message;
}
public void getMessage() {
System.out.println(“Your Message: ” + message);
}
}
Recommended: Hibernate Course in Chennai.
Spring Boot
Spring Boot makes it easier to create Spring applications by offering embedded servers and auto-configuration.
Create a Spring Boot Application
- To create a project, use Spring Initializr.
- Add dependencies such as DevTools for Spring Web and Spring Boot.
- Build a basic REST controller:
Example:
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@GetMapping(“/hello”)
public String sayHello() {
return “Hello, Spring Boot!”;
}
}
Run the application and visit http://localhost:8080/hello.
Gain expertise with advanced Java skills with our J2EE training in Chennai.
Key Features of Spring
The key features of Spring are:
- Dependency Injection (DI): This fundamental idea makes it possible for components to be loosely coupled, which improves the modularity, testability, and maintainability of your system.
- Aspect-Oriented Programming (AOP): Logging, security, and transaction management are examples of cross-cutting issues that can be modularized with aspect-oriented programming, or AOP.
- Data Access Abstraction: Spring’s support for JDBC, JPA, and other data access technologies makes database interactions easier.
- Web MVC Framework: For creating web applications, Spring MVC offers a stable and adaptable framework.
- Testing Support: Mocking and integration testing support are two of Spring’s great testing features.
Explore all software training courses for a bright IT career.
Conclusion
This Spring Tutorial offers a fundamental overview of Spring. You may create complex apps and explore the framework’s features in further detail with more research. Learn Spring Boot from scratch with this comprehensive tutorial. Leverage our Spring Boot course in Chennai for a promising career in Java app development.
