在SpringBoot3中spring.factories配置不起作用的原因和解决方法

在SpringBoot3中spring.factories配置的自动装配不生效

失效原因

从 Spring Boot 2.6 升级到Spring Boot 2.7后，自动配置注册有更改。 Spring Boot 2.7发行说明

废弃说明：

如果您创建了自己的自动配置，则应将注册从密钥spring.factories下移至org.springframework.boot.autoconfigure.AutoConfiguration.imports。每行包含自动配置类的完全限定名称，而不是单个逗号分隔的列表。有关示例，请参阅包含的自动配置。
为了向后兼容，spring.factories仍将保留中的条目。

• 在Spring Boot 2.7还是可以兼容使用spring.factories
• 到了SpringBoot3 spring.factories就不兼容使用了。
• tips: 在SpringBoot3中spring.factories使用org.springframework.boot.env.EnvironmentPostProcessor动态加载配置文件配置文件却还生效的。

解决办法

使用spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports代替spring.factories中的org.springframework.boot.autoconfigure.EnableAutoConfiguration

例子

• 原spring.factories文件

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.Test1AutoConfiguration,\
org.springframework.boot.autoconfigure.Test2AutoConfiguration,\

• 在resource/META-INF目录下新建spring目录，并添加org.springframework.boot.autoconfigure.AutoConfiguration.imports文件

org.springframework.boot.autoconfigure.Test1AutoConfiguration
org.springframework.boot.autoconfigure.Test2AutoConfiguration

springboot2.x 和springboot3  Autoconfiguration 对比图

springboot3 读取配置文件源码

private static final String LOCATION = "META-INF/spring/%s.imports";


	protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
		List<String> configurations = ImportCandidates.load(AutoConfiguration.class, getBeanClassLoader())
			.getCandidates();
		Assert.notEmpty(configurations,
				"No auto configuration classes found in "
						+ "META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports. If you "
						+ "are using a custom packaging, make sure that file is correct.");
		return configurations;
	}



	public static ImportCandidates load(Class<?> annotation, ClassLoader classLoader) {
		Assert.notNull(annotation, "'annotation' must not be null");
		ClassLoader classLoaderToUse = decideClassloader(classLoader);
		String location = String.format(LOCATION, annotation.getName());
		Enumeration<URL> urls = findUrlsInClasspath(classLoaderToUse, location);
		List<String> importCandidates = new ArrayList<>();
		while (urls.hasMoreElements()) {
			URL url = urls.nextElement();
			importCandidates.addAll(readCandidateConfigurations(url));
		}
		return new ImportCandidates(importCandidates);
	}

 

springboot2  读取配置文件源码

 

	
public static final String FACTORIES_RESOURCE_LOCATION = "META-INF/spring.factories";

protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
		List<String> configurations = SpringFactoriesLoader.loadFactoryNames(getSpringFactoriesLoaderFactoryClass(),
				getBeanClassLoader());
		Assert.notEmpty(configurations, "No auto configuration classes found in META-INF/spring.factories. If you "
				+ "are using a custom packaging, make sure that file is correct.");
		return configurations;
	}


	public static List<String> loadFactoryNames(Class<?> factoryType, @Nullable ClassLoader classLoader) {
		String factoryTypeName = factoryType.getName();
		return loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList());
	}