Beans and Dependency Injection

In Spring Boot, we can use Spring Framework to define our beans and their dependency injection. The@ComponentScan annotation is used to find beans and the corresponding injected with@Autowired annotation.

If you followed the Spring Boot typical layout, no need to specify any arguments for@ComponentScan annotation. All component class files are automatically registered with Spring Beans.

The following example provides an idea about Auto wiring the Rest Template object and creating a Bean for the same −

@Beanpublic RestTemplate getRestTemplate() {   return new RestTemplate();}

The following code shows the code for auto wired Rest Template object and Bean creation object in main Spring Boot Application class file −

DemoApplication.java

package com.tutorialspoint.demo;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.context.annotation.Bean;import org.springframework.web.client.RestTemplate;@SpringBootApplicationpublic class DemoApplication {@Autowired   RestTemplate restTemplate;      public static void main(String[] args) {      SpringApplication.run(DemoApplication.class, args);   }   @Bean   public RestTemplate getRestTemplate() {      return new RestTemplate();      }}