Spring 源码解析

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Spring 源码解析十三：SpringBoot 初始化应用时加载的组件

x33g5p2x  于2022-02-11 发布在 Spring  
字(27.6k)|赞(0)|评价(0)|浏览(576)

这些组件定义在 spring.factories
中

  1. # 日志系统
  2. org.springframework.boot.logging.LoggingSystemFactory=\
  3. org.springframework.boot.logging.logback.LogbackLoggingSystem.Factory,\
  4. org.springframework.boot.logging.log4j2.Log4J2LoggingSystem.Factory,\
  5. org.springframework.boot.logging.java.JavaLoggingSystem.Factory
  7. # 属性来源加载器
  8. org.springframework.boot.env.PropertySourceLoader=\
  9. org.springframework.boot.env.PropertiesPropertySourceLoader,\
  10. org.springframework.boot.env.YamlPropertySourceLoader
  12. # 配置数据来源解析器
  13. org.springframework.boot.context.config.ConfigDataLocationResolver=\
  14. org.springframework.boot.context.config.ConfigTreeConfigDataLocationResolver,\
  15. org.springframework.boot.context.config.StandardConfigDataLocationResolver
  17. # 配置数据加载器
  18. org.springframework.boot.context.config.ConfigDataLoader=\
  19. org.springframework.boot.context.config.ConfigTreeConfigDataLoader,\
  20. org.springframework.boot.context.config.StandardConfigDataLoader
  22. # 应用运行监听器
  23. org.springframework.boot.SpringApplicationRunListener=\
  24. org.springframework.boot.context.event.EventPublishingRunListener
  26. # 错误报告器
  27. org.springframework.boot.SpringBootExceptionReporter=\
  28. org.springframework.boot.diagnostics.FailureAnalyzers
  30. # 应用上下文初始加载器
  31. org.springframework.context.ApplicationContextInitializer=\
  32. org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,\
  33. org.springframework.boot.context.ContextIdApplicationContextInitializer,\
  34. org.springframework.boot.context.config.DelegatingApplicationContextInitializer,\
  35. org.springframework.boot.rsocket.context.RSocketPortInfoApplicationContextInitializer,\
  36. org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer
  38. # 应用监听器
  39. org.springframework.context.ApplicationListener=\
  40. org.springframework.boot.ClearCachesApplicationListener,\
  41. org.springframework.boot.builder.ParentContextCloserApplicationListener,\
  42. org.springframework.boot.context.FileEncodingApplicationListener,\
  43. org.springframework.boot.context.config.AnsiOutputApplicationListener,\
  44. org.springframework.boot.context.config.DelegatingApplicationListener,\
  45. org.springframework.boot.context.logging.LoggingApplicationListener,\
  46. org.springframework.boot.env.EnvironmentPostProcessorApplicationListener
  48. # 环境后置处理器
  49. org.springframework.boot.env.EnvironmentPostProcessor=\
  50. org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
  51. org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor,\
  52. org.springframework.boot.env.RandomValuePropertySourceEnvironmentPostProcessor,\
  53. org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor,\
  54. org.springframework.boot.env.SystemEnvironmentPropertySourceEnvironmentPostProcessor,\
  55. org.springframework.boot.reactor.DebugAgentEnvironmentPostProcessor
  57. # 失败分析器
  58. org.springframework.boot.diagnostics.FailureAnalyzer=\
  59. org.springframework.boot.context.config.ConfigDataNotFoundFailureAnalyzer,\
  60. org.springframework.boot.context.properties.IncompatibleConfigurationFailureAnalyzer,\
  61. org.springframework.boot.context.properties.NotConstructorBoundInjectionFailureAnalyzer,\
  62. org.springframework.boot.diagnostics.analyzer.BeanCurrentlyInCreationFailureAnalyzer,\
  63. org.springframework.boot.diagnostics.analyzer.BeanDefinitionOverrideFailureAnalyzer,\
  64. org.springframework.boot.diagnostics.analyzer.BeanNotOfRequiredTypeFailureAnalyzer,\
  65. org.springframework.boot.diagnostics.analyzer.BindFailureAnalyzer,\
  66. org.springframework.boot.diagnostics.analyzer.BindValidationFailureAnalyzer,\
  67. org.springframework.boot.diagnostics.analyzer.UnboundConfigurationPropertyFailureAnalyzer,\
  68. org.springframework.boot.diagnostics.analyzer.ConnectorStartFailureAnalyzer,\
  69. org.springframework.boot.diagnostics.analyzer.NoSuchMethodFailureAnalyzer,\
  70. org.springframework.boot.diagnostics.analyzer.NoUniqueBeanDefinitionFailureAnalyzer,\
  71. org.springframework.boot.diagnostics.analyzer.PortInUseFailureAnalyzer,\
  72. org.springframework.boot.diagnostics.analyzer.ValidationExceptionFailureAnalyzer,\
  73. org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyNameFailureAnalyzer,\
  74. org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyValueFailureAnalyzer,\
  75. org.springframework.boot.diagnostics.analyzer.PatternParseFailureAnalyzer,\
  76. org.springframework.boot.liquibase.LiquibaseChangelogMissingFailureAnalyzer
  78. # 失败分析报告器
  79. org.springframework.boot.diagnostics.FailureAnalysisReporter=\
  80. org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter

1. 日志系统

  1. org.springframework.boot.logging.LoggingSystemFactory=\
  2. org.springframework.boot.logging.logback.LogbackLoggingSystem.Factory,\
  3. org.springframework.boot.logging.log4j2.Log4J2LoggingSystem.Factory,\
  4. org.springframework.boot.logging.java.JavaLoggingSystem.Factory

配置中说明 SpringBoot 内置支持 logback、logback、java原生三种日志处理，具体源代码可以自行探索

2. 属性来源加载器

  1. org.springframework.boot.env.PropertySourceLoader=\
  2. org.springframework.boot.env.PropertiesPropertySourceLoader,\
  3. org.springframework.boot.env.YamlPropertySourceLoader

配置中说明 SpringBoot 内置支持 application*.properties、application*.yaml 两种文件格式加载属性配置来源，具体源代码可以自行探索

3. 配置数据来源解析器 & 配置数据加载器

  1. # 配置数据来源解析器
  2. org.springframework.boot.context.config.ConfigDataLocationResolver=\
  3. org.springframework.boot.context.config.ConfigTreeConfigDataLocationResolver,\
  4. org.springframework.boot.context.config.StandardConfigDataLocationResolver
  6. # 配置数据加载器
  7. org.springframework.boot.context.config.ConfigDataLoader=\
  8. org.springframework.boot.context.config.ConfigTreeConfigDataLoader,\
  9. org.springframework.boot.context.config.StandardConfigDataLoader

这一组放在一起解析，是因为他们一起完成了一个功能：

  1. ConfigDataLocationResolver
    将 spring.config.import、spring.config.addtional-location、spring.config.location 等资源定位路径下的
    application*.[properties/yaml] 资源解析成 ConfigDataResource
    资源对象，等待加载
  2. ConfigDataLoader
    将解析好的资源对象进行加载，把 ConfigDataResource 转换成 ConfigData
    （ConfigData 是一组 PropertySource）
  3. 将加载好的 ConfigData 添加到上下文对象中

ConfigTreeConfigDataLocationResolver
与 ConfigTreeConfigDataLoader
主要是读取 Kubernetes Volume 的 configMap 配置，这里就不做解析了

3.1. StandardConfigDataLocationResolver

StandardConfigDataLocationResolver
的主要功能是解析外部配置文件

  1. public class StandardConfigDataLocationResolver
  2.         implements ConfigDataLocationResolver<StandardConfigDataResource>, Ordered {
  3.     public StandardConfigDataLocationResolver(Log logger, Binder binder, ResourceLoader resourceLoader) {
  4.         // 加载 `spring.factories` 中的属性加载器，properties+yaml
  5.         this.propertySourceLoaders = SpringFactoriesLoader.loadFactories(PropertySourceLoader.class,
  6.                 getClass().getClassLoader());
  7.         // 获取 `spring.config.name` 指定的应用名称，默认是 `application`
  8.         this.configNames = getConfigNames(binder);
  10.         // ... 代码省略
  11.     }
  13.     // 解析路径 location
  14.     @Override
  15.     public List<StandardConfigDataResource> resolve(ConfigDataLocationResolverContext context,
  16.             ConfigDataLocation location) throws ConfigDataNotFoundException {
  17.         // 获取数据引用，然后解析
  18.         return resolve(getReferences(context, location));
  19.     }
  21.     // 获取数据引用
  22.     private Set<StandardConfigDataReference> getReferences(ConfigDataLocationResolverContext context,
  23.             ConfigDataLocation configDataLocation) {
  24.         // 获取资源位置
  25.         String resourceLocation = getResourceLocation(context, configDataLocation);
  26.         try {
  27.             // 如果是目录，就按目录加载
  28.             if (isDirectory(resourceLocation)) {
  29.                 // 加载目录下所有的 application*.[properties/yaml] 文件配置
  30.                 return getReferencesForDirectory(configDataLocation, resourceLocation, NO_PROFILE);
  31.             }
  32.             // 不然就按文件加载，获取指定文件的引用
  33.             return getReferencesForFile(configDataLocation, resourceLocation, NO_PROFILE);
  34.         }
  35.         catch (RuntimeException ex) {
  36.             // ... 代码省略
  37.         }
  38.     }
  40.     // 解析路径 location 中指定profile的文件
  41.     @Override
  42.     public List<StandardConfigDataResource> resolveProfileSpecific(ConfigDataLocationResolverContext context,
  43.             ConfigDataLocation location, Profiles profiles) {
  44.         // 获取数据引用，然后解析
  45.         return resolve(getProfileSpecificReferences(context, location, profiles));
  46.     }
  48.     // 获取指定profile的数据引用
  49.     private Set<StandardConfigDataReference> getProfileSpecificReferences(ConfigDataLocationResolverContext context,
  50.             ConfigDataLocation configDataLocation, Profiles profiles) {
  51.         Set<StandardConfigDataReference> references = new LinkedHashSet<>();
  52.         // 获取资源位置
  53.         String resourceLocation = getResourceLocation(context, configDataLocation);
  54.         // 遍历profiles加载
  55.         for (String profile : profiles) {
  56.             references.addAll(getReferences(configDataLocation, resourceLocation, profile));
  57.         }
  58.         return references;
  59.     }
  60. }
  1. public class StandardConfigDataLocationResolver
  2.         implements ConfigDataLocationResolver<StandardConfigDataResource>, Ordered {
  3.     // 获取资源位置
  4.     private String getResourceLocation(ConfigDataLocationResolverContext context,
  5.             ConfigDataLocation configDataLocation) {
  6.         // 去掉"resource:"前缀
  7.         String resourceLocation = configDataLocation.getNonPrefixedValue(PREFIX);
  8.         // 如果是以 / 开头或者是 [protocol]: 开头的，就算是绝对路径，直接返回
  9.         boolean isAbsolute = resourceLocation.startsWith("/") || URL_PREFIX.matcher(resourceLocation).matches();
  10.         if (isAbsolute) {
  11.             return resourceLocation;
  12.         }
  13.         // 否则以相对路径对待，加载父路径前缀再返回
  14.         ConfigDataResource parent = context.getParent();
  15.         if (parent instanceof StandardConfigDataResource) {
  16.             String parentResourceLocation = ((StandardConfigDataResource) parent).getReference().getResourceLocation();
  17.             String parentDirectory = parentResourceLocation.substring(0, parentResourceLocation.lastIndexOf("/") + 1);
  18.             return parentDirectory + resourceLocation;
  19.         }
  20.         return resourceLocation;
  21.     }
  23.     // 解析StandardConfigDataReference为StandardConfigDataResource
  24.     private List<StandardConfigDataResource> resolve(Set<StandardConfigDataReference> references) {
  25.         List<StandardConfigDataResource> resolved = new ArrayList<>();
  26.         for (StandardConfigDataReference reference : references) {
  27.             resolved.addAll(resolve(reference));
  28.         }
  29.         if (resolved.isEmpty()) {
  30.             resolved.addAll(resolveEmptyDirectories(references));
  31.         }
  32.         return resolved;
  33.     }
  34. }

3.2. StandardConfigDataLoader

StandardConfigDataLoader
的主要功能是读取外部配置文件里的值

  1. public class StandardConfigDataLoader implements ConfigDataLoader<StandardConfigDataResource> {
  2.     // 加载文件为ConfigData
  3.     @Override
  4.     public ConfigData load(ConfigDataLoaderContext context, StandardConfigDataResource resource)
  5.             throws IOException, ConfigDataNotFoundException {
  6.         // ... 代码省略
  8.         StandardConfigDataReference reference = resource.getReference();
  9.         Resource originTrackedResource = OriginTrackedResource.of(resource.getResource(),
  10.                 Origin.from(reference.getConfigDataLocation()));
  11.         String name = String.format("Config resource '%s' via location '%s'", resource,
  12.                 reference.getConfigDataLocation());
  13.         // 读取为propertySources
  14.         List<PropertySource<?>> propertySources = reference.getPropertySourceLoader().load(name, originTrackedResource);
  15.         return new ConfigData(propertySources);
  16.     }
  18. }

4. 应用运行监听器

  1. org.springframework.boot.SpringApplicationRunListener=\
  2. org.springframework.boot.context.event.EventPublishingRunListener

EventPublishingRunListener
的主要功能是发布应用事件，调用事件监听函数

5. 错误报告器

  1. org.springframework.boot.SpringBootExceptionReporter=\
  2. org.springframework.boot.diagnostics.FailureAnalyzers

FailureAnalyzers
的主要功能是向用户报告程序错误

6. 应用上下文初始加载器

  1. org.springframework.context.ApplicationContextInitializer=\
  2. org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,\
  3. org.springframework.boot.context.ContextIdApplicationContextInitializer,\
  4. org.springframework.boot.context.config.DelegatingApplicationContextInitializer,\
  5. org.springframework.boot.rsocket.context.RSocketPortInfoApplicationContextInitializer,\
  6. org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer

这些类都比较简单，以 ConfigurationWarningsApplicationContextInitializer
为例解析

  1. public class ConfigurationWarningsApplicationContextInitializer
  2.         implements ApplicationContextInitializer<ConfigurableApplicationContext> {
  3.     // 初始化组件
  4.     @Override
  5.     public void initialize(ConfigurableApplicationContext context) {
  6.         context.addBeanFactoryPostProcessor(new ConfigurationWarningsPostProcessor(getChecks()));
  7.     }
  9.     protected static final class ConfigurationWarningsPostProcessor
  10.             implements PriorityOrdered, BeanDefinitionRegistryPostProcessor {
  11.         // bean定义后置处理
  12.         @Override
  13.         public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
  14.             for (Check check : this.checks) {
  15.                 // 如果 @ComponentScan 扫描了 org.springframework 或 org，则警告错误
  16.                 String message = check.getWarning(registry);
  17.                 if (StringUtils.hasLength(message)) {
  18.                     warn(message);
  19.                 }
  20.             }
  22.         }
  24.     }
  25. }

7. 应用监听器

  1. org.springframework.context.ApplicationListener=\
  2. org.springframework.boot.ClearCachesApplicationListener,\
  3. org.springframework.boot.builder.ParentContextCloserApplicationListener,\
  4. org.springframework.boot.context.FileEncodingApplicationListener,\
  5. org.springframework.boot.context.config.AnsiOutputApplicationListener,\
  6. org.springframework.boot.context.config.DelegatingApplicationListener,\
  7. org.springframework.boot.context.logging.LoggingApplicationListener,\
  8. org.springframework.boot.env.EnvironmentPostProcessorApplicationListener

这些类都比较简单，可以自行探索

8. 环境后置处理器

  1. org.springframework.boot.env.EnvironmentPostProcessor=\
  2. org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
  3. org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor,\
  4. org.springframework.boot.env.RandomValuePropertySourceEnvironmentPostProcessor,\
  5. org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor,\
  6. org.springframework.boot.env.SystemEnvironmentPropertySourceEnvironmentPostProcessor,\
  7. org.springframework.boot.reactor.DebugAgentEnvironmentPostProcessor

8.1. CloudFoundryVcapEnvironmentPostProcessor

CloudFoundryVcapEnvironmentPostProcessor
的主要功能是支持 CloudFoundry（一个开源 PaaS 云平台）

8.2. ConfigDataEnvironmentPostProcessor

ConfigDataEnvironmentPostProcessor
的主要功能是加载和应用 ConfigData 到 Spring 环境中

  1. public class ConfigDataEnvironmentPostProcessor implements EnvironmentPostProcessor, Ordered {
  2.     @Override
  3.     public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
  4.         postProcessEnvironment(environment, application.getResourceLoader(), application.getAdditionalProfiles());
  5.     }
  7.     void postProcessEnvironment(ConfigurableEnvironment environment, ResourceLoader resourceLoader,
  8.             Collection<String> additionalProfiles) {
  9.         try {
  10.             // 获取资源加载器
  11.             resourceLoader = (resourceLoader != null) ? resourceLoader : new DefaultResourceLoader();
  12.             // 加载和应用
  13.             getConfigDataEnvironment(environment, resourceLoader, additionalProfiles).processAndApply();
  14.         }
  15.         catch (UseLegacyConfigProcessingException ex) {
  16.             // ... 代码省略
  17.         }
  18.     }
  20.     // 获取环境对象
  21.     ConfigDataEnvironment getConfigDataEnvironment(ConfigurableEnvironment environment, ResourceLoader resourceLoader,
  22.             Collection<String> additionalProfiles) {
  23.         return new ConfigDataEnvironment(this.logFactory, this.bootstrapContext, environment, resourceLoader,
  24.                 additionalProfiles, this.environmentUpdateListener);
  25.     }
  26. }

实际加载与应用是由 ConfigDataEnvironment
完成的

  1. class ConfigDataEnvironment {
  2.     // 用于覆盖默认属性加载的地方
  3.     static final String LOCATION_PROPERTY = "spring.config.location";
  5.     // 默认之外，其他属性加载的地方
  6.     static final String ADDITIONAL_LOCATION_PROPERTY = "spring.config.additional-location";
  8.     // 导入第三方属性文件
  9.     static final String IMPORT_PROPERTY = "spring.config.import";
  11.     // 默认属性加载的地方
  12.     // 1. 加载 classpath:/application*.yaml
  13.     // 2. 加载 classpath:/config/application*.yaml
  14.     // 3. 加载 file:./application*.yaml
  15.     // 4. 加载 file:./config/application*.yaml
  16.     // 5. 加载 file:./config/*/application*.yaml
  17.     static final ConfigDataLocation[] DEFAULT_SEARCH_LOCATIONS;
  18.     static {
  19.         List<ConfigDataLocation> locations = new ArrayList<>();
  20.         locations.add(ConfigDataLocation.of("optional:classpath:/"));
  21.         locations.add(ConfigDataLocation.of("optional:classpath:/config/"));
  22.         locations.add(ConfigDataLocation.of("optional:file:./"));
  23.         locations.add(ConfigDataLocation.of("optional:file:./config/"));
  24.         locations.add(ConfigDataLocation.of("optional:file:./config/*/"));
  25.         DEFAULT_SEARCH_LOCATIONS = locations.toArray(new ConfigDataLocation[0]);
  26.     }
  28.     // 属性值提供器
  29.     private final ConfigDataEnvironmentContributors contributors;
  31.     ConfigDataEnvironment(DeferredLogFactory logFactory, ConfigurableBootstrapContext bootstrapContext,
  32.             ConfigurableEnvironment environment, ResourceLoader resourceLoader, Collection<String> additionalProfiles,
  33.             ConfigDataEnvironmentUpdateListener environmentUpdateListener) {
  34.         // ... 代码省略
  36.         // 创建默认的属性值提供器
  37.         this.contributors = createContributors(binder);
  38.     }
  40.     // 创建默认的属性值提供器
  41.     private ConfigDataEnvironmentContributors createContributors(Binder binder) {
  42.         // 获取属性值来源
  43.         MutablePropertySources propertySources = this.environment.getPropertySources();
  44.         // 结果集
  45.         List<ConfigDataEnvironmentContributor> contributors = new ArrayList<>(propertySources.size() + 10);
  46.         // 默认的属性值来源
  47.         PropertySource<?> defaultPropertySource = null;
  48.         for (PropertySource<?> propertySource : propertySources) {
  49.             // default properties
  50.             if (DefaultPropertiesPropertySource.hasMatchingName(propertySource)) {
  51.                 defaultPropertySource = propertySource;
  52.             }
  53.             // 其他的
  54.             else {
  55.                 contributors.add(ConfigDataEnvironmentContributor.ofExisting(propertySource));
  56.             }
  57.         }
  58.         // 获取默认的提供器
  59.         contributors.addAll(getInitialImportContributors(binder));
  60.         // 如果有默认的，添加到最后面
  61.         if (defaultPropertySource != null) {
  62.             contributors.add(ConfigDataEnvironmentContributor.ofExisting(defaultPropertySource));
  63.         }
  64.         // 创建 ConfigDataEnvironmentContributors
  65.         return createContributors(contributors);
  66.     }
  68.     // 获取默认的提供器
  69.     private List<ConfigDataEnvironmentContributor> getInitialImportContributors(Binder binder) {
  70.         // 结果集
  71.         List<ConfigDataEnvironmentContributor> initialContributors = new ArrayList<>();
  72.         // 添加 `spring.config.import` 指定的资源
  73.         addInitialImportContributors(initialContributors, bindLocations(binder, IMPORT_PROPERTY, EMPTY_LOCATIONS));
  74.         // 添加 `spring.config.additional-location` 指定的资源
  75.         addInitialImportContributors(initialContributors,
  76.                 bindLocations(binder, ADDITIONAL_LOCATION_PROPERTY, EMPTY_LOCATIONS));
  77.         // 添加 `spring.config.location` 指定的资源
  78.         // （会覆盖默认属性加载的地方：classpath:/, classpath:/config/, file:./, file:./config/, file:./config/*/）
  79.         addInitialImportContributors(initialContributors,
  80.                 bindLocations(binder, LOCATION_PROPERTY, DEFAULT_SEARCH_LOCATIONS));
  81.         return initialContributors;
  82.     }
  83. }
  1. class ConfigDataEnvironment {
  2.     // 处理及应用
  3.     void processAndApply() {
  4.         // 创建 ConfigDataImporter
  5.         ConfigDataImporter importer = new ConfigDataImporter(this.logFactory, this.notFoundAction, this.resolvers,
  6.                 this.loaders);
  7.         // 绑定 contributors
  8.         registerBootstrapBinder(this.contributors, null, DENY_INACTIVE_BINDING);
  9.         // 导入 `spring.config.import` 指定的资源，重新绑定 contributors
  10.         ConfigDataEnvironmentContributors contributors = processInitial(this.contributors, importer);
  11.         // 创建一个配置数据激活上下文对象，如果绑定到了没有active的属性源，则报错
  12.         // 比如：spring.profiles.active=prod，但绑定了 application-dev.yaml
  13.         ConfigDataActivationContext activationContext = createActivationContext(
  14.                 contributors.getBinder(null, BinderOption.FAIL_ON_BIND_TO_INACTIVE_SOURCE));
  15.         // 导入无 profile `application.yaml` 的资源，重新绑定 contributors
  16.         contributors = processWithoutProfiles(contributors, importer, activationContext);
  17.         // 载入profiles到绑定的上下文中
  18.         activationContext = withProfiles(contributors, activationContext);
  19.         // 导入激活 profile `application-[active].yaml` 的资源，重新绑定 contributors
  20.         contributors = processWithProfiles(contributors, importer, activationContext);
  21.         // 应用到环境中
  22.         applyToEnvironment(contributors, activationContext);
  23.     }
  25.     // 导入 `spring.config.import` 指定的资源，重新绑定 contributors
  26.     private ConfigDataEnvironmentContributors processInitial(ConfigDataEnvironmentContributors contributors,
  27.             ConfigDataImporter importer) {
  28.         contributors = contributors.withProcessedImports(importer, null);
  29.         registerBootstrapBinder(contributors, null, DENY_INACTIVE_BINDING);
  30.         return contributors;
  31.     }
  33.     // 导入无 profile `application.yaml` 的资源，重新绑定 contributors
  34.     private ConfigDataEnvironmentContributors processWithoutProfiles(ConfigDataEnvironmentContributors contributors,
  35.             ConfigDataImporter importer, ConfigDataActivationContext activationContext) {
  36.         contributors = contributors.withProcessedImports(importer, activationContext);
  37.         registerBootstrapBinder(contributors, activationContext, DENY_INACTIVE_BINDING);
  38.         return contributors;
  39.     }
  41.     // 载入profiles到绑定的上下文中
  42.     private ConfigDataActivationContext withProfiles(ConfigDataEnvironmentContributors contributors,
  43.             ConfigDataActivationContext activationContext) {
  44.         // 获取绑定对象
  45.         Binder binder = contributors.getBinder(activationContext,
  46.                 ConfigDataEnvironmentContributor::isNotIgnoringProfiles, BinderOption.FAIL_ON_BIND_TO_INACTIVE_SOURCE);
  47.         try {
  48.             // 参数输入的profiles
  49.             Set<String> additionalProfiles = new LinkedHashSet<>(this.additionalProfiles);
  50.             // 载入当前激活环境中 `spring.profiles.include` 指定的其他环境
  51.             additionalProfiles.addAll(getIncludedProfiles(contributors, activationContext));
  52.             // 创建 Profiles 对象，载入到上下文中
  53.             Profiles profiles = new Profiles(this.environment, binder, additionalProfiles);
  54.             return activationContext.withProfiles(profiles);
  55.         }
  56.         catch (BindException ex) {
  57.             // ... 代码省略
  58.         }
  59.     }
  61.     // 导入激活 profile `application-[active].yaml` 的资源，重新绑定 contributors
  62.     private ConfigDataEnvironmentContributors processWithProfiles(ConfigDataEnvironmentContributors contributors,
  63.             ConfigDataImporter importer, ConfigDataActivationContext activationContext) {
  64.         contributors = contributors.withProcessedImports(importer, activationContext);
  65.         registerBootstrapBinder(contributors, activationContext, ALLOW_INACTIVE_BINDING);
  66.         return contributors;
  67.     }
  69.     // 应用到环境中
  70.     private void applyToEnvironment(ConfigDataEnvironmentContributors contributors,
  71.             ConfigDataActivationContext activationContext) {
  72.         // ... 代码省略
  74.         // 属性来源
  75.         MutablePropertySources propertySources = this.environment.getPropertySources();
  76.         // 遍历contributors
  77.         for (ConfigDataEnvironmentContributor contributor : contributors) {
  78.             PropertySource<?> propertySource = contributor.getPropertySource();
  80.             // ... 代码省略
  82.             // 如果是激活的，加入到环境的propertySources中
  83.             if (contributor.isActive(activationContext)) {
  84.                 propertySources.addLast(propertySource);
  85.             }
  86.         }
  88.         // ... 代码省略
  89.     }
  90. }

实际资源载入是由 ConfigDataEnvironmentContributors
完成的

  1. class ConfigDataEnvironmentContributors implements Iterable<ConfigDataEnvironmentContributor> {
  2.     // 处理载入属性值
  3.     ConfigDataEnvironmentContributors withProcessedImports(ConfigDataImporter importer,
  4.             ConfigDataActivationContext activationContext) {
  5.         // 每次载入新的文件后，都返回一个新的对象
  6.         ConfigDataEnvironmentContributors result = this;
  7.         int processed = 0;
  8.         while (true) {
  9.             // 获取下一个可以载入的文件
  10.             ConfigDataEnvironmentContributor contributor = getNextToProcess(result, activationContext, importPhase);
  11.             // 没有下一个了，返回
  12.             if (contributor == null) {
  13.                 return result;
  14.             }
  16.             // 非导入其他文件
  17.             if (contributor.getKind() == Kind.UNBOUND_IMPORT) {
  18.                 // 配置属性源
  19.                 Iterable<ConfigurationPropertySource> sources = Collections
  20.                         .singleton(contributor.getConfigurationPropertySource());
  21.                 // 占位符解析器
  22.                 PlaceholdersResolver placeholdersResolver = new ConfigDataEnvironmentContributorPlaceholdersResolver(
  23.                         result, activationContext, true);
  24.                 // 新建绑定
  25.                 Binder binder = new Binder(sources, placeholdersResolver, null, null, null);
  26.                 // 生成一个新的ConfigDataEnvironmentContributor
  27.                 ConfigDataEnvironmentContributor bound = contributor.withBoundProperties(binder);
  28.                 // 生成一个新的对象
  29.                 result = new ConfigDataEnvironmentContributors(this.logger, this.bootstrapContext,
  30.                         result.getRoot().withReplacement(contributor, bound));
  31.                 continue;
  32.             }
  34.             // 路径解析上下文
  35.             ConfigDataLocationResolverContext locationResolverContext = new ContributorConfigDataLocationResolverContext(
  36.                     result, contributor, activationContext);
  37.             // 加载上下文
  38.             ConfigDataLoaderContext loaderContext = new ContributorDataLoaderContext(this);
  39.             // 获取导入的资源路径
  40.             List<ConfigDataLocation> imports = contributor.getImports();
  41.             // 导入资源为ConfigData
  42.             Map<ConfigDataResolutionResult, ConfigData> imported = importer.resolveAndLoad(activationContext,
  43.                     locationResolverContext, loaderContext, imports);
  44.             // 合并当前与上一次的属性值
  45.             ConfigDataEnvironmentContributor contributorAndChildren = contributor.withChildren(importPhase,
  46.                     asContributors(imported));
  47.             // 生成一个新的对象
  48.             result = new ConfigDataEnvironmentContributors(this.logger, this.bootstrapContext,
  49.                     result.getRoot().withReplacement(contributor, contributorAndChildren));
  50.             processed++;
  51.         }
  52.     }
  53. }

8.3. CloudFoundryVcapEnvironmentPostProcessor

CloudFoundryVcapEnvironmentPostProcessor
的主要功能是支持以random.开头的属性配置转换成实际的随机值

8.4. SpringApplicationJsonEnvironmentPostProcessor

SpringApplicationJsonEnvironmentPostProcessor
的主要功能是支持用 spring.application.json 参数或 SPRING_APPLICATION_JSON 环境变量作为初始化参数传入 JSON 数据

  1. public class SpringApplicationJsonEnvironmentPostProcessor implements EnvironmentPostProcessor, Ordered {
  2.     @Override
  3.     public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
  4.         // 获取属性来源
  5.         MutablePropertySources propertySources = environment.getPropertySources();
  6.         // 流式处理 `spring.application.json` 参数或 `SPRING_APPLICATION_JSON` 环境变量
  7.         propertySources.stream().map(JsonPropertyValue::get).filter(Objects::nonNull).findFirst()
  8.                 .ifPresent((v) -> processJson(environment, v));
  9.     }
  11.     private void processJson(ConfigurableEnvironment environment, JsonPropertyValue propertyValue) {
  12.         // 获取JSON解析器
  13.         JsonParser parser = JsonParserFactory.getJsonParser();
  14.         // 解析成Map
  15.         Map<String, Object> map = parser.parseMap(propertyValue.getJson());
  16.         // 有值
  17.         if (!map.isEmpty()) {
  18.             // 添加为一个JSON来源
  19.             addJsonPropertySource(environment, new JsonPropertySource(propertyValue, flatten(map)));
  20.         }
  21.     }
  22. }
  1. public abstract class JsonParserFactory {
  2.     public static JsonParser getJsonParser() {
  3.         // 默认首先使用Jackson
  4.         if (ClassUtils.isPresent("com.fasterxml.jackson.databind.ObjectMapper", null)) {
  5.             return new JacksonJsonParser();
  6.         }
  7.         // 其次使用Gson
  8.         if (ClassUtils.isPresent("com.google.gson.Gson", null)) {
  9.             return new GsonJsonParser();
  10.         }
  11.         // 其次使用Yaml
  12.         if (ClassUtils.isPresent("org.yaml.snakeyaml.Yaml", null)) {
  13.             return new YamlJsonParser();
  14.         }
  15.         // 都没有，使用内置的
  16.         return new BasicJsonParser();
  17.     }
  19. }

8.5. SystemEnvironmentPropertySourceEnvironmentPostProcessor

SystemEnvironmentPropertySourceEnvironmentPostProcessor
的主要功能是处理 systemEnvironment 属性来源

8.6. DebugAgentEnvironmentPostProcessor

DebugAgentEnvironmentPostProcessor
的主要功能是处理 spring.reactor.debug-agent.enabled

9. 失败分析器

  1. org.springframework.boot.diagnostics.FailureAnalyzer=\
  2. org.springframework.boot.context.config.ConfigDataNotFoundFailureAnalyzer,\
  3. org.springframework.boot.context.properties.IncompatibleConfigurationFailureAnalyzer,\
  4. org.springframework.boot.context.properties.NotConstructorBoundInjectionFailureAnalyzer,\
  5. org.springframework.boot.diagnostics.analyzer.BeanCurrentlyInCreationFailureAnalyzer,\
  6. org.springframework.boot.diagnostics.analyzer.BeanDefinitionOverrideFailureAnalyzer,\
  7. org.springframework.boot.diagnostics.analyzer.BeanNotOfRequiredTypeFailureAnalyzer,\
  8. org.springframework.boot.diagnostics.analyzer.BindFailureAnalyzer,\
  9. org.springframework.boot.diagnostics.analyzer.BindValidationFailureAnalyzer,\
  10. org.springframework.boot.diagnostics.analyzer.UnboundConfigurationPropertyFailureAnalyzer,\
  11. org.springframework.boot.diagnostics.analyzer.ConnectorStartFailureAnalyzer,\
  12. org.springframework.boot.diagnostics.analyzer.NoSuchMethodFailureAnalyzer,\
  13. org.springframework.boot.diagnostics.analyzer.NoUniqueBeanDefinitionFailureAnalyzer,\
  14. org.springframework.boot.diagnostics.analyzer.PortInUseFailureAnalyzer,\
  15. org.springframework.boot.diagnostics.analyzer.ValidationExceptionFailureAnalyzer,\
  16. org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyNameFailureAnalyzer,\
  17. org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyValueFailureAnalyzer,\
  18. org.springframework.boot.diagnostics.analyzer.PatternParseFailureAnalyzer,\
  19. org.springframework.boot.liquibase.LiquibaseChangelogMissingFailureAnalyzer

这些类都比较简单，可以自行探索

10. 失败分析报告器

  1. org.springframework.boot.diagnostics.FailureAnalysisReporter=\
  2. org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter

LoggingFailureAnalysisReporter
的主要功能是应用启动失败，报告原因 APPLICATION FAILED TO START

后续

更多博客，查看 https://github.com/senntyou/blogs

作者：深予之 (@senntyou)

版权声明：自由转载-非商用-非衍生-保持署名（创意共享 3.0 许可证）

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