今天使用 springcloud 整合 Eureka 出现了问题，eureka 注册中心 module 启动无法加载 bootstrap.yml 后来改成 bootstrap.properties 才可以使用，特此记录下来。

错误:

IllegalStateException: Failed to load property source from location 'classpath:/bootstrap.yml'

15:49:06.555 [main] ERROR org.springframework.boot.SpringApplication - Application run failed
java.lang.IllegalStateException: Failed to load property source from location 'classpath:/bootstrap.yml'
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:538)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadForFileExtension(ConfigFileApplicationListener.java:497)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:465)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.lambda$null$6(ConfigFileApplicationListener.java:447)
	at java.lang.Iterable.forEach(Iterable.java:75)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.lambda$load$7(ConfigFileApplicationListener.java:446)
	at java.lang.Iterable.forEach(Iterable.java:75)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:443)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:335)
	at org.springframework.boot.context.config.ConfigFileApplicationListener.addPropertySources(ConfigFileApplicationListener.java:214)
	at org.springframework.boot.context.config.ConfigFileApplicationListener.postProcessEnvironment(ConfigFileApplicationListener.java:197)
	at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent(ConfigFileApplicationListener.java:184)
	at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent(ConfigFileApplicationListener.java:170)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127)
	at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:74)
	at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54)
	at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:358)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:317)
	at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:137)
	at org.springframework.cloud.bootstrap.BootstrapApplicationListener.bootstrapServiceContext(BootstrapApplicationListener.java:197)
	at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:104)
	at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:70)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127)
	at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:74)
	at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54)
	at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:358)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:317)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243)
	at cn.org.wbw.ConfigClientApplication.main(ConfigClientApplication.java:17)
Caused by: org.yaml.snakeyaml.error.YAMLException: java.nio.charset.MalformedInputException: Input length = 1
	at org.yaml.snakeyaml.reader.StreamReader.update(StreamReader.java:254)
	at org.yaml.snakeyaml.reader.StreamReader.<init>(StreamReader.java:58)
	at org.yaml.snakeyaml.Yaml.loadAll(Yaml.java:537)
	at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:166)
	at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:139)
	at org.springframework.boot.env.OriginTrackedYamlLoader.load(OriginTrackedYamlLoader.java:75)
	at org.springframework.boot.env.YamlPropertySourceLoader.load(YamlPropertySourceLoader.java:50)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadDocuments(ConfigFileApplicationListener.java:556)
	at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:518)
	... 35 common frames omitted
Caused by: java.nio.charset.MalformedInputException: Input length = 1
	at java.nio.charset.CoderResult.throwException(CoderResult.java:281)
	at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:339)
	at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
	at java.io.InputStreamReader.read(InputStreamReader.java:184)
	at org.yaml.snakeyaml.reader.UnicodeReader.read(UnicodeReader.java:125)
	at org.yaml.snakeyaml.reader.StreamReader.update(StreamReader.java:223)
	... 43 common frames omitted

SpringBoot默认支持properties和YAML两种格式的配置文件。前者格式简单，但是只支持键值对。如果需要表达列表，最好使用YAML格式。SpringBoot支持自动加载约定名称的配置文件，例如application.yml。

一、bootstrap.yml（.properties）与 application.yml（.properties）执行顺序

bootstrap.yml（bootstrap.properties）

    用来程序引导时执行，应用于更加早期配置信息读取，如可以使用来配置application.yml中使用到参数等

application.yml（application.properties) 

    应用程序特有配置信息，可以用来配置后续各个模块中需使用的公共参数等。

bootstrap.yml 先于 application.yml 加载。

二、 当使用Spring Cloud Config Server时，需要将 spring.application.name 和spring.cloud.config.server.git.uri 写入 bootstrap.yml。

三、 一些 encryption/decryption（加密/解密）存储在 bootstrap.yml 里面。

四、bootstrap.yml 被 Spring ApplicationContext 的父类加载，这个类先于加载application.yml 的 ApplicatonContext 启动。