# WARNING: This is wrong for multi-config generators because they don't use
#          and typically don't even set CMAKE_BUILD_TYPE
string(TOLOWER ${CMAKE_BUILD_TYPE} build_type)
if (build_type STREQUAL debug)
  target_compile_definitions(exe1 PRIVATE DEBUG_BUILD)
endif()

# Works correctly for both single and multi-config generators
target_compile_definitions(exe1 PRIVATE
  $<$<CONFIG:Debug>:DEBUG_BUILD>
)

@Override
public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
	registerDefaultConfiguration(metadata, registry);
	// 调用方法
	registerFeignClients(metadata, registry);
}

public void registerFeignClients(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
	LinkedHashSet<BeanDefinition> candidateComponents = new LinkedHashSet<>();
	Map<String, Object> attrs = metadata.getAnnotationAttributes(EnableFeignClients.class.getName());
	final Class<?>[] clients = attrs == null ? null : (Class<?>[]) attrs.get("clients");
	if (clients == null || clients.length == 0) {
	    ClassPathScanningCandidateComponentProvider scanner = getScanner();
	    scanner.setResourceLoader(this.resourceLoader);
	    scanner.addIncludeFilter(new AnnotationTypeFilter(FeignClient.class));
	    Set<String> basePackages = getBasePackages(metadata);
	    for (String basePackage : basePackages) {
	        candidateComponents.addAll(scanner.findCandidateComponents(basePackage));
	    }
	}
	else {
	    // 这里，通过EnableFeignClients中的clients()方法直接创建了BeanDefinition（BeanDefinition
	    // 是非常重要的关于Bean的一个类，请阅读Spring源码）
	    for (Class<?> clazz : clients) {
	        // AnnotatedGenericBeanDefinition是BeanDefinition的实现类。
	        candidateComponents.add(new AnnotatedGenericBeanDefinition(clazz));
	    }
	}
	
	for (BeanDefinition candidateComponent : candidateComponents) {
	    if (candidateComponent instanceof AnnotatedBeanDefinition beanDefinition) {
	        // verify annotated class is an interface
	        AnnotationMetadata annotationMetadata = beanDefinition.getMetadata();
	        // 看到这个断言，@FeignClient只能直接接口
	        Assert.isTrue(annotationMetadata.isInterface(), "@FeignClient can only be specified on an interface");

	        Map<String, Object> attributes = annotationMetadata
	        		.getAnnotationAttributes(FeignClient.class.getCanonicalName());

	        String name = getClientName(attributes);
	        String className = annotationMetadata.getClassName();
	        registerClientConfiguration(registry, name, className, attributes.get("configuration"));

	        registerFeignClient(registry, annotationMetadata, attributes);
		}
	}
}

public class SpringApplication {

    //...

	private Set<Class<?>> primarySources;

	private Set<String> sources = new LinkedHashSet<>();
	
	//...
	
	public void addPrimarySources(Collection<Class<?>> additionalPrimarySources) {
		this.primarySources.addAll(additionalPrimarySources);
	}
	
	public void setSources(Set<String> sources) {
		Assert.notNull(sources, "Sources must not be null");
		this.sources = new LinkedHashSet<>(sources);
	}
}

   // SpringApplication.class
protected void load(ApplicationContext context, Object[] sources) {
	if (logger.isDebugEnabled()) {
		logger.debug("Loading source " + StringUtils.arrayToCommaDelimitedString(sources));
	}
	// BeanDefinitionLoader是用于load环境的帮助类
	BeanDefinitionLoader loader = createBeanDefinitionLoader(getBeanDefinitionRegistry(context), sources);
	if (this.beanNameGenerator != null) {
		loader.setBeanNameGenerator(this.beanNameGenerator);
	}
	if (this.resourceLoader != null) {
		loader.setResourceLoader(this.resourceLoader);
	}
	if (this.environment != null) {
		loader.setEnvironment(this.environment);
	}
	loader.load();
}

private Class<?> nextProviderClass() {
    if (configs == null) {
        try {
            // 注意这里的PREFIX被限定为META-INF/services
            String fullName = PREFIX + service.getName();
            if (loader == null) {
                configs = ClassLoader.getSystemResources(fullName);
            } else if (loader == ClassLoaders.platformClassLoader()) {
                // The platform classloader doesn't have a class path,
                // but the boot loader might.
                if (BootLoader.hasClassPath()) {
                    configs = BootLoader.findResources(fullName);
                } else {
                    configs = Collections.emptyEnumeration();
                }
            } else {
                configs = loader.getResources(fullName);
            }
        } catch (IOException x) {
            fail(service, "Error locating configuration files", x);
        }
    }
    while ((pending == null) || !pending.hasNext()) {
        if (!configs.hasMoreElements()) {
            return null;
        }
        pending = parse(configs.nextElement());
    }
    String cn = pending.next();
    try {
        return Class.forName(cn, false, loader);
    } catch (ClassNotFoundException x) {
        fail(service, "Provider " + cn + " not found");
        return null;
    }
}

<deb_dir>
    |
    |-----DEBIAN
    |      |-----control
    |
    |-----opt
    |      |-----lib_name
    |               |-----bin
    |               |-----include
    |               |-----lib

--skip-grant-tables将跳过grant tables，同时拒绝远程访问，并且给予任何人
unrestricted access to all databases（不受限制地访问所有数据库）。

MariaDB [(none)] > FLUSH PRIVILEGES;

To cause a server started with --skip-grant-tables to load the grant tables at runtime, perform a privilege-flushing operation, which can be done in these ways:

     Issue a MySQL FLUSH PRIVILEGES statement after connecting to the server.

     Execute a mysqladmin flush-privileges or mysqladmin reload command from the command line.

MariaDB [(none)] > ALTER USER 'root'@'localhost' IDENTIFIED BY '<your_passcode>';