分布式配置中心config-client配置报错：java.lang.IllegalStateException: duplicate key: spring

今天练习分布式配置中心，写config-client配置文件，使用bootstrap.properties配置，运行没有问题。

bootstrap.properties：

spring.application.name=config-client
spring.cloud.config.label=master
spring.cloud.config.profile=dev
spring.cloud.config.uri= http://localhost:8888/
server.port=8881

#spring.cloud.config.label 指明远程仓库的分支

#spring.cloud.config.profile

#dev开发环境配置文件
#test测试环境
#pro正式环境
#spring.cloud.config.uri= http://localhost:8888/ 指明配置服务中心的网址。

#spring.cloud.config.discovery.enabled 是从配置中心读取文件。
#spring.cloud.config.discovery.serviceId 配置中心的servieId，即服务名

但是我使用了bootstrap.yml配置文件，启动报错：

bootstrap.yml：

spring:
  application:
    name: config-client
server:
  port: 8881

spring:
  cloud:
    config:
      label: master
      profile: dev
      uri: http://localhost:8888/

报错如下：

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$6(ConfigFileApplicationListener.java:447)
    at java.lang.Iterable.forEach(Unknown Source)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.lambda$load$7(ConfigFileApplicationListener.java:446)
    at java.lang.Iterable.forEach(Unknown Source)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$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.itcast.com.ConfigClientApplication.main(ConfigClientApplication.java:22)
Caused by: java.lang.IllegalStateException: duplicate key: spring
    at org.yaml.snakeyaml.constructor.SafeConstructor.processDuplicateKeys(SafeConstructor.java:99)
    at org.yaml.snakeyaml.constructor.SafeConstructor.flattenMapping(SafeConstructor.java:70)
    at org.yaml.snakeyaml.constructor.SafeConstructor.constructMapping2ndStep(SafeConstructor.java:182)
    at org.yaml.snakeyaml.constructor.BaseConstructor.constructMapping(BaseConstructor.java:443)
    at org.yaml.snakeyaml.constructor.SafeConstructor$ConstructYamlMap.construct(SafeConstructor.java:519)
    at org.yaml.snakeyaml.constructor.BaseConstructor.constructObjectNoCheck(BaseConstructor.java:207)
    at org.yaml.snakeyaml.constructor.BaseConstructor.constructObject(BaseConstructor.java:196)
    at org.springframework.boot.env.OriginTrackedYamlLoader$OriginTrackingConstructor.constructObject(OriginTrackedYamlLoader.java:94)
    at org.yaml.snakeyaml.constructor.BaseConstructor.constructDocument(BaseConstructor.java:161)
    at org.yaml.snakeyaml.constructor.BaseConstructor.getData(BaseConstructor.java:127)
    at org.yaml.snakeyaml.Yaml$1.next(Yaml.java:547)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:166)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:139)
    at org.springframework.boot.env.OriginTrackedYamlLoader.load(OriginTrackedYamlLoader.java:75)
    at org.springframework.boot.env.YamlPropertySourceLoader.load(YamlPropertySourceLoader.java:50)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadDocuments(ConfigFileApplicationListener.java:556)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:518)
    ... 35 common frames omitted

报错信息显示无法加载配置文件，原因是重复建“spring”。

解决：yml文件在单一文件中，可用连续三个连字号（---）区分多个文件。更改bootstrap.yml：

spring:
  application:
    name: config-client
server:
  port: 8881
---
spring:
  cloud:
    config:
      label: master
      profile: dev
      uri: http://localhost:8888/

重启，运行成功。