Hands-On Full Stack Development with Spring Boot 2 and React - Second Edition

DI in Spring Boot

Spring Boot scans your application classes and register classes with certain annotations (@Service, @Repository, @Controller) as Spring Beans. These beans can then be injected using an @Autowired annotation:

public class Car {   @Autowired   private Owner owner;       ...}

A fairly common situation is where we need database access for some operations, and, in Spring Boot, we are using repository classes for that. In this situation, we can inject repository class and start to use its methods:

public class Car {   @Autowired   private CarRepository carRepository;       // Fetch all cars from db    carRepositoty.findAll();    ...}

Java (javax.annotation) also provides a @Resource annotation that can be used to inject resources. You can define the ...