class AutoConfigurationImportSelector{

    /**
     * 获取所有的类信息
     */
    protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
        List<String> configurations = new ArrayList<>(
                //加载 META-INF/spring.factories 下面的信息
                SpringFactoriesLoader.loadFactoryNames(getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader()));
        ImportCandidates.load(AutoConfiguration.class, getBeanClassLoader()).forEach(configurations::add);
        Assert.notEmpty(configurations,
                "No auto configuration classes found in META-INF/spring.factories nor 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;
    }
}