Kotlin actual combat: troubleshooting failure to obtain local configuration files and remote Apollo configuration

background

As a JVM scripting language, Kotlin is favored by many Java developers.

The project uses Java+Kotlin mixed programming. In Spring Boot application development, configurations that will not change are placed in the local configuration file, and configurations that may change are placed in the remote Apollo Server.

question

Because of business needs, it is necessary to add a configuration that may be continuously updated, and then if elsejudge it through logic.

Apollo configuration:
Insert image description here
The hard coding in the screenshot below is the back-up solution for the unresolved problem:

Console printing:

In fact, when developing locally, it is customary to implement the business logic first. At the beginning, there was no new configuration in Apollo screen.channel, but using The hard coding method in Figure 2 above:

@Value("\${screen.channel: xhwjk_screen}")
var screenChannel: String? = null

This method does not read the local configuration file, nor does it read the Apollo Server configuration. It directly sets a default value, that is, xhwjk_screenduring breakpoint debugging, the data cannot be obtained.

bootstrap.ymlAdd configuration in local file:

screen:
  channel: xhwjk_screen,pdwjk_screen

I also application.ymltried adding the same configuration items.

The conclusion is: the configuration cannot be obtained.

Compared

The same configuration can be placed in a Java Controller without any problem:

@Slf4j
@RestController
@RequestMapping("/dialog")
public class AuthenticationCheckController {
    
    
    @Value("${screen.channel: xhwjk_screen}")
    private String screenChannel;

    @GetMapping(value = "/authentication")
    @ResponseStatus(HttpStatus.NO_CONTENT)
    public void checkAuthentication() {
    
    
        LOGGER.info("ff:{}", screenChannel);
        // This resource just returns a 204 No Content in case the request is authenticated.
    }
}

Console prints:

AuthenticationCheckController | checkAuthentication | 28 | - ff:xhwjk_screen,pdwjk_screen

Note:
JDK version: OpenJDK-11
Spring Boot version: 2.1.6.RELEASE
Spring Cloud version: Greenwich.RELEASE
Kotlin version: 1.3.72

troubleshooting

Try 1

Searching with the problem phenomenon described above, I found stackoverflow-how-to-get-value-from-application-yml-in-springboot .

Apollo adds a new configuration:
Insert image description here
adds a new configuration DialogConfig.ktclass:

@Component
@ConfigurationProperties("dialog")
class DialogConfig {
    
    
    var screenChannel: String? = null
}

Quoting this configuration:

@Resource
private val dialogConfig: DialogConfig? = null

Still can't get the configuration:
Insert image description here

Try 2

Found another stackoverflow-how-to-get-variable-from-spring-application-yaml-in-kotlin)
or the one above DialogConfig.kt, quoting the configuration:

@Resource
lateinit var dialogConfig: DialogConfig

Report an error directly:
kotlin.UninitializedPropertyAccessException: lateinit property dialogConfig has not been initialized
Insert image description here
Reference: stackoverflow-uninitializedpropertyaccessexception . Make a judgment before using it. There is no need to judge, and you still cannot get the data.

Try 3

DialogConfig becomes a Java class:

@Component
@ConfigurationProperties("dialog")
public class DialogConfig {
    
    
    public String screenChannel;
}

Quoting this configuration:

@Resource
var dialogConfig: DialogConfig? = null

Or not!
Insert image description here

solve

There is really no way, hard coding solves the problem, refer to screenshot 1.

Vomited. .

Bald.