spring-boot - @ConditionalOnMissingBean 不能被覆盖

Question

我正在使用 Spring Boot 2.1.6.RELEASE，我想知道应该如何使用 @ConditionalOnMissingBean ？

配置示例:

@Configuration
public class MyAutoConfiguration {

  @Bean
  @ConditionalOnMissingBean
  public Foo foo() {
    return new Foo();
  }
}

@Configuration
@Import(MyAutoConfiguration.class)
public class AppConfiguration {

  @Bean
  public Foo foo() {
    return new Foo("some property");
  }
}

AppConfiguration.class 和 MyAutoConfiguration.class 位于不同的模块中。

错误:

The bean 'foo', defined in class path resource [com/example/autoconf/configuration/AppConfiguration.class], could not be registered. A bean with that name has already been defined in class path resource [com/my/configuration/MyAutoConfiguration.class] and overriding is disabled.

如何在不设置spring.main.allow-bean-definition-overriding=true属性的情况下使用@ConditionalOnMissingBean？

Answer 1

要使 MyAutoConfiguration 被 Spring Boot 选择为自动配置，需要在 META-INF/spring.factories 中声明，如下所示

org.springframework.boot.autoconfigure.EnableAutoConfiguration=x.y.z.MyAutoConfiguration 

有关自定义自动配置的更多详细信息，请查看 here .