Spring Boot @Autowired vs @Resource
October 01, 2023
@Autowired and Jakarta @Resource annotations in our Spring Boot application.
1. The Spring
@Autowired and @Resource both annotations are used to resolve dependency injection.
2. The
@Autowired annotation can be applied on fields, constructors, and methods. The @Resource annotation can be applied on fields and methods and not on constructors.
3. The
@Autowired annotated method can have multi-arguments whereas @Resource annotated method can have only single argument.
4. The
@Autowired as well as @Resource annotation can be applied on private fields, too.
@Autowired
Spring@Autowired annotation marks a constructor, field, setter method, or config method as to be autowired by dependency injection. Find its element.
required : Boolean value to decide if annotated dependency is required.
Example :
Address.java
@Component
public class Address {
public String getCityName() {
return "PrayagRaj";
}
}
@Component
public class Customer {
public String getName() {
return "Mahesh";
}
}
@Service
public class CustomerService {
private Customer customer;
private Address address;
@Autowired
public CustomerService(Customer customer, Address address) {
this.customer = customer;
this.address = address;
}
public Address getAddress() {
return address;
}
public Customer getCustomer() {
return customer;
}
}
@SpringBootApplication
public class SpringBootAppStarter {
public static void main(String[] args) throws Exception {
ConfigurableApplicationContext ctx = SpringApplication.run(SpringBootAppStarter.class, args);
CustomerService service = ctx.getBean(CustomerService.class);
System.out.println(service.getCustomer().getName());
System.out.println(service.getAddress().getCityName());
ctx.close();
}
}
Mahesh PrayagRaj
@Resource
1. The@Resource annotation is from jakarta.annotation package. This annotation may be applied to class, field or method level.
2. When the
@Resource annotation is applied at method and field level, the container will inject the requested resource into the application component on class initialization.
3. When the
@Resource annotation is applied at class level, the annotation declares a resource that the application will look up at runtime.
4. The
@Resource annotation can also be applied on private field.
Find the elements of
@Resource annotation.
authenticationType : Authentication type to use for the resource.
description : Description of the resource.
lookup : Name of the resource that the reference points to.
mappedName : A product-specific name that this resource should be mapped to.
name : The JNDI name of the resource.
shareable : Boolean value to decide if the resource can be shared between this component and other components.
type : The Java type of the resource.
Example :
CustomerService.java
@Service
public class CustomerService {
@Resource
private Customer customer;
@Resource
private Address address;
public Address getAddress() {
return address;
}
public Customer getCustomer() {
return customer;
}
}
