spring - 如何将@ConfigurationProperties Autowiring 到@Configuration中？

Question

我有一个如下定义的属性类:

@Validated
@ConfigurationProperties(prefix = "plugin.httpclient")
public class HttpClientProperties {
   ...
}

还有一个像这样的配置类:

@Configuration
@EnableScheduling
public class HttpClientConfiguration {

    private final HttpClientProperties httpClientProperties;

    @Autowired
    public HttpClientConfiguration(HttpClientProperties httpClientProperties) {
        this.httpClientProperties = httpClientProperties;
    }

    ...
}

当启动我的 Spring Boot 应用程序时，我得到了

Parameter 0 of constructor in x.y.z.config.HttpClientConfiguration required a bean of type 'x.y.z.config.HttpClientProperties' that could not be found.

这不是一个有效的用例，还是我必须以某种方式声明依赖项？

Answer 1

这是一个有效的用例，但是，您的 HttpClientProperties 未被拾取，因为组件扫描器未扫描它们。您可以使用 @Component 注释您的 HttpClientProperties:

@Validated
@Component
@ConfigurationProperties(prefix = "plugin.httpclient")
public class HttpClientProperties {
    // ...
}

另一种方法(如 Stephane Nicoll 中所述)是在 Spring 配置类上使用 @EnableConfigurationProperties() 注释，例如:

@EnableConfigurationProperties(HttpClientProperties.class) // This is the recommended way
@EnableScheduling
public class HttpClientConfiguration {
    // ...
}

Spring boot docs 中也对此进行了描述.