@PropertySource解析原理

 

关键类
ConfigurationClassParser

# ConfigurationClass 标注@Configuration注解的类

@Nullable
	protected final SourceClass doProcessConfigurationClass(ConfigurationClass configClass, SourceClass sourceClass)
			throws IOException {

		if (configClass.getMetadata().isAnnotated(Component.class.getName())) {
			// Recursively process any member (nested) classes first
			processMemberClasses(configClass, sourceClass);
		}

		// Process any @PropertySource annotations 处理PropertySources 
		for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable(
				sourceClass.getMetadata(), PropertySources.class,
				org.springframework.context.annotation.PropertySource.class)) {
			if (this.environment instanceof ConfigurableEnvironment) {
				processPropertySource(propertySource);
			}
			else {
				logger.info("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() +
						"]. Reason: Environment must implement ConfigurableEnvironment");
			}
		}

  .....................

}

 

# 关注 addPropertySource(factory.createPropertySource(name, new EncodedResource(resource, encoding)));

private void processPropertySource(AnnotationAttributes propertySource) throws IOException {
		String name = propertySource.getString("name");
		if (!StringUtils.hasLength(name)) {
			name = null;
		}
		String encoding = propertySource.getString("encoding");
		if (!StringUtils.hasLength(encoding)) {
			encoding = null;
		}
		String[] locations = propertySource.getStringArray("value");
		Assert.isTrue(locations.length > 0, "At least one @PropertySource(value) location is required");
		boolean ignoreResourceNotFound = propertySource.getBoolean("ignoreResourceNotFound");

		Class factoryClass = propertySource.getClass("factory");
		PropertySourceFactory factory = (factoryClass == PropertySourceFactory.class ?
				DEFAULT_PROPERTY_SOURCE_FACTORY : BeanUtils.instantiateClass(factoryClass));

		for (String location : locations) {
			try {
				String resolvedLocation = this.environment.resolveRequiredPlaceholders(location);
				Resource resource = this.resourceLoader.getResource(resolvedLocation);
				addPropertySource(factory.createPropertySource(name, new EncodedResource(resource, encoding))); // 添加到propertySources
			}
			catch (IllegalArgumentException | FileNotFoundException | UnknownHostException ex) {
				// Placeholders not resolvable or resource not found when trying to open it
				if (ignoreResourceNotFound) {
					if (logger.isInfoEnabled()) {
						logger.info("Properties location [" + location + "] not resolvable: " + ex.getMessage());
					}
				}
				else {
					throw ex;
				}
			}
		}
	}

 

 

# propertySources.addLast(propertySource);  // 添加到最后

private void addPropertySource(PropertySource propertySource) {
		String name = propertySource.getName();
		MutablePropertySources propertySources = ((ConfigurableEnvironment) this.environment).getPropertySources();

		if (this.propertySourceNames.contains(name)) {
			// We've already added a version, we need to extend it
			PropertySource existing = propertySources.get(name);
			if (existing != null) {
				PropertySource newSource = (propertySource instanceof ResourcePropertySource ?
						((ResourcePropertySource) propertySource).withResourceName() : propertySource);
				if (existing instanceof CompositePropertySource) {
					((CompositePropertySource) existing).addFirstPropertySource(newSource);
				}
				else {
					if (existing instanceof ResourcePropertySource) {
						existing = ((ResourcePropertySource) existing).withResourceName();
					}
					CompositePropertySource composite = new CompositePropertySource(name);
					composite.addPropertySource(newSource);
					composite.addPropertySource(existing);
					propertySources.replace(name, composite);
				}
				return;
			}
		}

		if (this.propertySourceNames.isEmpty()) {
			propertySources.addLast(propertySource);  // 添加到最后
		}
		else {
			String firstProcessed = this.propertySourceNames.get(this.propertySourceNames.size() - 1);
			propertySources.addBefore(firstProcessed, propertySource);
		}
		this.propertySourceNames.add(name);
	}

 

propertySources.addLast(propertySource)