spring - 使用 spring.factories 加载自定义自动配置时出现 FileNotFoundException

Question

更新:如果我简单地添加extension，我也会遇到同样的错误。项目作为 master 的依赖项.

更新 2:我创建了一个 Github 存储库来重现错误:https://github.com/papagno/spring-factories-test

<小时/>

我正在尝试使用 Spring Boot 和 spring.factories 文件。所以我创建了两个简单的项目:

• 大师:
  • 这是一个 Spring Boot 应用程序 (1.4.3)，以 starter-web 和 starter-actuator 作为依赖项。
  • 我还添加了<layout>ZIP</layout>作为 spring-boot-maven-plugin 的配置.

• 扩展

  • 这是一个简单的 Spring Boot 应用程序 (1.4.3)，仅包含 spring-boot-starter作为依赖项。
  • 它在 resources/META-INF 中包含以下 spring.factories 文件:
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
my.package.extension.ExtensionAutoConfiguration


  • 它还包含 my.package.ExtensionAutoConfiguration仅用 @Configuration 注释的类并声明 @Bean :

    package my.package.extension;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    public class ExtensionAutoConfiguration
    {
        @Bean
        ExtensionService extensionService()
        {
            return new ExtensionService();
        }
    }
    

我使用 maven 编译这两个项目，将两个 jar 放在同一个文件夹中，然后使用以下命令运行 master:
java -Dloader.path=. -jar master-0.0.1-SNAPSHOT.jar


spring.factories被识别，但是当 Spring 尝试实例化我的自动配置类时，我得到 FileNotFoundException对于该类。

这是堆栈跟踪:

org.springframework.beans.factory.BeanDefinitionStoreException: Failed to process import candidates for configuration class [my.package.master.MasterApplication]; nested exception is java.lang.IllegalStateException: java.io.FileNotFoundException: class path resource [my/package/extension/ExtensionAutoConfiguration.class] cannot be opened because it does not exist
    at org.springframework.context.annotation.ConfigurationClassParser.processDeferredImportSelectors(ConfigurationClassParser.java:482) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:184) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:308) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:228) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:270) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:93) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:686) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:524) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) [spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) [spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at my.package.master.MasterApplication.main(MasterApplication.java:10) [classes!/:0.0.1-SNAPSHOT]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
    at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) [master-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) [master-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) [master-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
    at org.springframework.boot.loader.PropertiesLauncher.main(PropertiesLauncher.java:521) [master-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
Caused by: java.lang.IllegalStateException: java.io.FileNotFoundException: class path resource [my/package/extension/ExtensionAutoConfiguration.class] cannot be opened because it does not exist
    at org.springframework.boot.autoconfigure.EnableAutoConfigurationImportSelector.selectImports(EnableAutoConfigurationImportSelector.java:94) ~[spring-boot-autoconfigure-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassParser.processDeferredImportSelectors(ConfigurationClassParser.java:474) ~[spring-context-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    ... 22 common frames omitted
Caused by: java.io.FileNotFoundException: class path resource [my/package/extension/ExtensionAutoConfiguration.class] cannot be opened because it does not exist
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:172) ~[spring-core-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.core.type.classreading.SimpleMetadataReader.<init>(SimpleMetadataReader.java:50) ~[spring-core-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:98) ~[spring-core-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.createMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:89) ~[spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.getMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:76) ~[spring-boot-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:93) ~[spring-core-4.3.5.RELEASE.jar!/:4.3.5.RELEASE]
    at org.springframework.boot.autoconfigure.AutoConfigurationSorter$AutoConfigurationClasses.<init>(AutoConfigurationSorter.java:110) ~[spring-boot-autoconfigure-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.autoconfigure.AutoConfigurationSorter.getInPriorityOrder(AutoConfigurationSorter.java:54) ~[spring-boot-autoconfigure-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.autoconfigure.EnableAutoConfigurationImportSelector.sort(EnableAutoConfigurationImportSelector.java:193) ~[spring-boot-autoconfigure-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    at org.springframework.boot.autoconfigure.EnableAutoConfigurationImportSelector.selectImports(EnableAutoConfigurationImportSelector.java:89) ~[spring-boot-autoconfigure-1.4.3.RELEASE.jar!/:1.4.3.RELEASE]
    ... 23 common frames omitted

我做错了什么吗？我可以做什么来了解正在发生的事情？谢谢。

Answer 1

您的扩展不得是 Spring Boot 应用程序(无父 spring-boot-starter-parent)。

当您将 spring-boot-starter-parent 声明为父级时，生成的 jar 会使用 Sring-Boot 风格重新打包，并且类不在预期的文件夹中。如果打开extension-0.0.1-SNAPSHOT.jar，类位于BOOT-INF/classes中，因此当该jar用作库时，找不到类。这些类需要位于 jar 内的根目录中。

将以下 pom.xml 用于扩展项目:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>extension</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>extension</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-parent</artifactId>
                <version>1.4.3.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>com.example</groupId>
            <artifactId>api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
</project>

在上面的代码示例中，我仍然将 spring-boot-starter-parent 声明为 dependencyManagement - import，因此版本声明是继承的。但是，spring-boot-maven-plugin不会被执行，jar不会被重新打包，并且可以作为库使用。