SpringBoot源码解析:Environment获取配置原理(2) |
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SpringBoot源码解析:Environment获取配置原理(2)
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debug的时候发现一个很有意思的事情，就是第二个元素configurationProperties中的ConfigurationPropertySourcesPropertySource 包含了外面所有的propertySource。
所以在获取bored.coupon.coupon-no配置值的时候，当遍历到name=configurationProperties时获取到ConfigurationPropertySourcesPropertySource。 然后在ConfigurationPropertySourcesPropertySource 中把这些配置又遍历了一遍，获取到之后就return了。 并没有如我们想象的遍历到PropertySource序号7的元素applicationConfig ConfigurationPropertySourcesPropertySource源码如下： class ConfigurationPropertySourcesPropertySource extends PropertySource implements OriginLookup { ConfigurationPropertySourcesPropertySource(String name, Iterable source) { super(name, source); } @Override public Object getProperty(String name) { ConfigurationProperty configurationProperty = findConfigurationProperty(name); return (configurationProperty != null) ? configurationProperty.getValue() : null; } private ConfigurationProperty findConfigurationProperty(String name) { try { return findConfigurationProperty(ConfigurationPropertyName.of(name, true)); } catch (Exception ex) { return null; } } private ConfigurationProperty findConfigurationProperty(ConfigurationPropertyName name) { if (name == null) { return null; } //最终在此处遍历的所有配置文件，获取的相关属性值 for (ConfigurationPropertySource configurationPropertySource : getSource()) { ConfigurationProperty configurationProperty = configurationPropertySource.getConfigurationProperty(name); if (configurationProperty != null) { return configurationProperty; } } return null; }疑惑，这是哪放进去的呢？前一篇有提到:SpringApplication的prepareEnvironment方法 private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments) { //2.1 Create and configure the environment 创建和配置environment ConfigurableEnvironment environment = getOrCreateEnvironment(); //2.2 加载启动命令行配置属性，active属性。（先不深入讲解） configureEnvironment(environment, applicationArguments.getSourceArgs()); //2.3 发布事件 listeners.environmentPrepared(environment); bindToSpringApplication(environment); if (!this.isCustomEnvironment) { environment = new EnvironmentConverter(getClassLoader()).convertEnvironmentIfNecessary(environment, deduceEnvironmentClass()); } //就是此处，把上述解析的所有配置文件PropertySources，添加到key为configurationProperties的PropertySource对象中，并添加到PropertySources的第一个元素中，我们可以深入一下看看 ConfigurationPropertySources.attach(environment); return environment; }ConfigurationPropertySources.attach(environment); public static void attach(Environment environment) { Assert.isInstanceOf(ConfigurableEnvironment.class, environment); //从environment中获取所有解析的配置MutablePropertySources MutablePropertySources sources = ((ConfigurableEnvironment) environment).getPropertySources(); PropertySource attached = sources.get(ATTACHED_PROPERTY_SOURCE_NAME); if (attached != null && attached.getSource() != sources) { sources.remove(ATTACHED_PROPERTY_SOURCE_NAME); attached = null; } if (attached == null) { //把上述MutablePropertySources封装到ConfigurationPropertySourcesPropertySource，重新添加到MutablePropertySources中 sources.addFirst(new ConfigurationPropertySourcesPropertySource(ATTACHED_PROPERTY_SOURCE_NAME, new SpringConfigurationPropertySources(sources))); } }为什么要引入ConfigurationPropertySourcesPropertySource？ 源码中看到直接通过name=configurationProperties获取ConfigurationPropertySourcesPropertySource 的暂时只有ConfigurationPropertySources类get方法， attach也是ConfigurationPropertySources这个类。 而此处的get方法就是提供给Binder类使用（我们继续往下看） ConfigurationPropertySources源码如下： public static Iterable get(Environment environment) { Assert.isInstanceOf(ConfigurableEnvironment.class, environment); MutablePropertySources sources = ((ConfigurableEnvironment) environment).getPropertySources(); ConfigurationPropertySourcesPropertySource attached = (ConfigurationPropertySourcesPropertySource) sources .get(ATTACHED_PROPERTY_SOURCE_NAME); if (attached == null) { return from(sources); } return attached.getSource(); } |
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