Step02.md

What You Will Learn during this Step:

• Lets add a RestController with a dependency and see Spring Boot Magic live

Theory Break : Quick Spring and Spring MVC Primer

• What is dependency?
• @Component
• @Autowired
• @RestController

Useful Snippets and References

package com.in28minutes.springboot;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class WelcomeController {

	//Auto wiring
	@Autowired
	private WelcomeService service;

	@RequestMapping("/welcome")
	public String welcome() {
		return service.retrieveWelcomeMessage();
	}
}

@Component
class WelcomeService {

	public String retrieveWelcomeMessage() {
		//Complex Method
		return "Good Morning updated";
	}
}

Files List

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.in28minutes.springboot</groupId>
	<artifactId>first-springboot-project</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.4.0.RELEASE</version>
	</parent>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

src/main/java/com/in28minutes/service/WelcomeService.java

package com.in28minutes.service;

import org.springframework.stereotype.Component;

@Component
public class WelcomeService {

	public String retrieveWelcomeMessage() {
		//Complex Method
		return "Good Morning updated";
	}
}

src/main/java/com/in28minutes/springboot/Application.java

package com.in28minutes.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan("com.in28minutes")
public class Application {

	public static void main(String[] args) {
		ApplicationContext ctx = SpringApplication.run(Application.class, args);

	}

}

src/main/java/com/in28minutes/springboot/WelcomeController.java

package com.in28minutes.springboot;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.in28minutes.service.WelcomeService;

@RestController
public class WelcomeController {

	//Auto wiring
	@Autowired
	private WelcomeService service;

	@RequestMapping("/welcome")
	public String welcome() {
		return service.retrieveWelcomeMessage();
	}
}