Spring @ConditionalOnBean 不阻止创建 bean

Question

I have several beans

AudioConfig.java

@ConstructorBinding
@ConfigurationProperties(prefix = "audio")
@AllArgsConstructor
@Getter
@ConditionalOnProperty("audio.root-path")
public class AudioConfig {
    private final Path rootPath;
}

AudioFileProvider.java

@Component
@AllArgsConstructor
@Log4j2
@ConditionalOnBean(AudioConfig.class)
public class AudioFileProvider {
     private final AudioConfig audioConfig;
     ....

AudioCleanser.kt

@ConditionalOnBean(AudioFileProvider::class)
class AudioCleanser(
    private val dslContext: DSLContext,
    private val audioFileProvider: AudioFileProvider
)

So if my property audio.root-path is not defined then it should not try to instantiate AudioCleanser, right?

Yet I get:

***************************
APPLICATION FAILED TO START
***************************

Description:

Parameter 1 of constructor in AudioCleanser required a bean of type 'AudioFileProvider' that could not be found.


Action:

Consider defining a bean of type 'AudioFileProvider' in your configuration.

Answer 1

You can do it in several ways:

1. Use all conditions in AudioCleanser :

@ConditionalOnBean({AudioFileProvider::class,AudioConfig::class})
class AudioCleanser(
    private val dslContext: DSLContext,
    private val audioFileProvider: AudioFileProvider
)

2. Use custom condition :

public class AudioEnabledCondition extends AllNestedConditions {

    public AudioEnabledCondition() {
        super(ConfigurationPhase.REGISTER_BEAN);
    }

    @ConditionalOnBean(AudioConfig.class)
    static class AudioConfigExistsCondition {

    }

    @ConditionalOnBean(AudioFileProvider.class)
    static class AudioFileProviderExistsCondition {

    }

}

@Conditional(AudioEnabledCondition::class)
class AudioCleanser(
    private val dslContext: DSLContext,
    private val audioFileProvider: AudioFileProvider
)