@ConfigurationProperties, @Value not Working YET Passing the Tests-CodePudding

I have a strange problem reading configuration, none of solutions I've seen seem to work. Here is my code:

@SpringBootApplication
@EnableConfigurationProperties
public class Application {
    
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Here is my properties class

@Component
@ConfigurationProperties(prefix = "my")
@Data
@ToString
@NoArgsConstructor
@AllArgsConstructor
public class MyProperties {
    private String host;
    private int port;
}

I then use MyProperties class in my class using @Autowired:

@Autowired
private MyProperties props;

However, I'm getting null for my props object.

Strangely, this is passing the tests just perfectly:

@SpringBootTest
class ApplicationTests {
    
    @Autowired
    private MyProperties props;
    
    @Test
    void test_configuration() {
        Assertions.assertEquals(props.getHost(), "xx.xx.xx.xx");//pass!
        Assertions.assertEquals(props.getPort(), xxxxxx);//pass!
    }
}

It has totally refused to work, and so has @Value injection. What could I be missing?

EDIT

Here's complete code of how I'm using @Autowired on MyProperties (I've included @Value which is also not working)

@Slf4j
@Component //also tried @Configurable, @Service
public class MyService {
    
    @Autowired
    private MyProperties props;
    
    @Value("localhost")
    public String host;
    
    public void post() {
        log.info(host   props);// =null and null
    }
}

EDIT2

However, I've noticed that on the controller, it works perfectly okay:

@Slf4j
@RestController
@Service
public class Main {
    
    @Autowired
    private MyProperties props;
    
    @Value("localhost")
    private String host;
    
    @GetMapping("/post")
    public void post() {
        log.info(host   props);//=it's perfect!
        new MyService().post();// calling MyService - where @Autowired or @Value is failing
    }
}

CodePudding user response：

The reason this isn't working is because the MyService you're using isn't a Spring bean, but an instance you created by yourself (using new MyService()).

To make this work, you should autowire MyService, in stead of creating your own instance:

@Slf4j
@RestController
public class Main {
    @Autowired // Autowire MyService
    private MyService myService;

    @GetMapping("/post")
    public void post() {
        myService.post(); // Use the myService field
    }
}

For more information, look at this Q&A: Why is my Spring @Autowired field null.

CodePudding user response：

1. Lombok

Some people use Project Lombok to add getters and setters automatically. Make sure that Lombok does not generate any particular constructor for such a type, as it is used automatically by the container to instantiate the object.

With "such a type" ConfigurationProperties is referred in Externalized Configuration (one of my favorite chapters;) More Exact: 2.8.1. JavaBean properties binding, at the bottom of second "Note!" ;)

So this could be a reason (for strange behavior).