检测到循环@Import

Question

• 我在使用 spring-boot version 之前几个月创建了 spring-boot 自动配置库1.3.0.RC1。

其结构为：

核心库

它包含扫描库中组件的 @Configuration 类。

@Configuration
@ComponentScan
public class CoreLibAutoConfiguration {

}

使用上述（核心）库创建的库。

它包含另一个@Configuration类。它的定义是

@Configuration
@Import(CoreLibAutoConfiguration.class)
@ComponentScan
public class MyLibAutoConfiguration {

}

它还包含spring.factories在其类路径中。其中包含在应用程序启动时自动配置该库的条目。

org.springframework.boot.autoconfigure.EnableAutoConfiguration=MyLibAutoConfiguration

---

现在我已将此库集成到我的 spring-boot Web 应用程序中，该应用程序再次使用相同的 spring-boot 版本1.3.0.RC1。

一切都按预期进行。

但是，现在正在开发另一个使用 spring-boot version 的 spring-boot Web 应用程序1.3.5.RELEASE。

我尝试将几个月前创建的相同库集成到我的新 Web 应用程序中。但我因与循环引用相关的错误而失败。堆栈跟踪是

org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: A circular @Import has been detected: Illegal attempt by @Configuration class 'MyLibAutoConfiguration' to import class 'MyLibAutoConfiguration' as 'MyLibAutoConfiguration' is already present in the current import stack [MyLibAutoConfiguration->Application]
Offending resource: class path resource [mylib/MyLibAutoConfiguration.class]
    at org.springframework.beans.factory.parsing.FailFastProblemReporter.error(FailFastProblemReporter.java:70) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:475) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:278) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:232) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:191) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:272) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:232) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:510) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:278) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:232) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:510) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processDeferredImportSelectors(ConfigurationClassParser.java:455) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:186) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:321) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:243) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:273) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:98) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:678) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:520) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at myapp.Application.main(Application.java:15) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
    at org.springframework.boot.maven.AbstractRunMojo$LaunchRunner.run(AbstractRunMojo.java:478) [spring-boot-maven-plugin-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_45]

如果我将 spring-boot 的版本更改为1.3.0.RC1我的新应用程序，它又可以正常工作。

我搜索了其背后的原因，发现了一个帖子https://jira.spring.io/browse/SPR-13101。它说这是由于配置类的嵌套造成的。

有人可以指导我找到解决我的问题的正确方法吗？

Answer 1

作为修复，我更新了自动配置库的配置。

我遵循的步骤是：

• 删除@Import为CoreLibAutoConfiguration
• 添加CoreLibAutoConfiguration到自动配置使用spring.factories
• MyLibAutoConfiguration应该在CoreLibAutoConfiguration初始化之后进行初始化。

最终代码将是：

MyLib自动配置

@Configuration
@ComponentScan
@AutoConfigureAfter(value = {CoreLibAutoConfiguration.class})    
public class MyLibAutoConfiguration {

}

弹簧工厂

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
CoreLibAutoConfiguration,\
MyLibAutoConfiguration

它对我来说效果很好。