第4 章：ConfigDataEnvironmentPostProcessor

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李延 LV6 2021-05-20

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# 作用

EnvironmentPostProcessor子类，environment的后置处理器。在environment创建完成后调用。主要作用是加载配置文件。

# postProcessEnvironment

我们直接关注它的postProcessEnvironment方法

```java
@Override
	public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
		postProcessEnvironment(environment, application.getResourceLoader(), application.getAdditionalProfiles());
	}

void postProcessEnvironment(ConfigurableEnvironment environment, ResourceLoader resourceLoader,
			Collection<String> additionalProfiles) {
		try {
			this.logger.trace("Post-processing environment to add config data");
			resourceLoader = (resourceLoader != null) ? resourceLoader : new DefaultResourceLoader();
			getConfigDataEnvironment(environment, resourceLoader, additionalProfiles).processAndApply();
		}
		catch (UseLegacyConfigProcessingException ex) {
			this.logger.debug(LogMessage.format("Switching to legacy config file processing [%s]",
					ex.getConfigurationProperty()));
			postProcessUsingLegacyApplicationListener(environment, resourceLoader);
		}
	}

ConfigDataEnvironment getConfigDataEnvironment(ConfigurableEnvironment environment, ResourceLoader resourceLoader,
			Collection<String> additionalProfiles) {
		return new ConfigDataEnvironment(this.logFactory, this.bootstrapContext, environment, resourceLoader,
				additionalProfiles);
	}

```

我们看到代码最后是调用了ConfigDataEnvironment对象的processAndApply方法

# ConfigDataEnvironment

## 静态方法

```java

static final ConfigDataLocation[] DEFAULT_SEARCH_LOCATIONS;
	static {
		List<ConfigDataLocation> locations = new ArrayList<>();
		locations.add(ConfigDataLocation.of("optional:classpath:/"));
		locations.add(ConfigDataLocation.of("optional:classpath:/config/"));
		locations.add(ConfigDataLocation.of("optional:file:./"));
		locations.add(ConfigDataLocation.of("optional:file:./config/*/"));
		locations.add(ConfigDataLocation.of("optional:file:./config/"));
		DEFAULT_SEARCH_LOCATIONS = locations.toArray(new ConfigDataLocation[0]);
	};

```

我们看到在静态方法中预设了5个文件路径，也就是我们在使用springboot时文件加载的路径。

## 构造方法

```java

ConfigDataEnvironment(DeferredLogFactory logFactory, ConfigurableBootstrapContext bootstrapContext,
			ConfigurableEnvironment environment, ResourceLoader resourceLoader, Collection<String> additionalProfiles) {
		Binder binder = Binder.get(environment);
		UseLegacyConfigProcessingException.throwIfRequested(binder);
		this.logFactory = logFactory;
		this.logger = logFactory.getLog(getClass());
		this.notFoundAction = binder.bind(ON_NOT_FOUND_PROPERTY, ConfigDataNotFoundAction.class)
				.orElse(ConfigDataNotFoundAction.FAIL);
		this.bootstrapContext = bootstrapContext;
		this.environment = environment;
		this.resolvers = createConfigDataLocationResolvers(logFactory, bootstrapContext, binder, resourceLoader);
		this.additionalProfiles = additionalProfiles;
		this.loaders = new ConfigDataLoaders(logFactory, bootstrapContext);
		this.contributors = createContributors(binder);
	}

```

//TODO 2.4的代码看不懂了。有事件再解析吧。

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