解決 Spring Boot v2.1.3.RELEASE 的 while scanning an alias 問題（附優雅停服shuntdown配置）
阿新 • • 發佈：2019-08-17
初學 Spring Boot 框架，在搭建“優雅停服”的時候遇到問題，怎麼也配置不通，有一系列問題（都是我自己的原因，太菜）。下面簡單說一下，首先，我是用的 application.yml 配置檔案進行配置的。這個就導致了配置以下
management.endpoints.web.exposure.include: *再啟動專案，會出現報錯：
09:56:06.571 [main] ERROR org.springframework.boot.SpringApplication - Application run failed java.lang.IllegalStateException: Failed to load property source from location 'classpath:/application.yml' at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:554) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadForFileExtension(ConfigFileApplicationListener.java:500) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:467) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.lambda$null$6(ConfigFileApplicationListener.java:448) at java.lang.Iterable.forEach(Iterable.java:75) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.lambda$load$7(ConfigFileApplicationListener.java:447) at java.lang.Iterable.forEach(Iterable.java:75) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:444) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:332) at org.springframework.boot.context.config.ConfigFileApplicationListener.addPropertySources(ConfigFileApplicationListener.java:207) at org.springframework.boot.context.config.ConfigFileApplicationListener.postProcessEnvironment(ConfigFileApplicationListener.java:190) at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent(ConfigFileApplicationListener.java:177) at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent(ConfigFileApplicationListener.java:163) 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:75) at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54) at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:347) at org.springframework.boot.SpringApplication.run(SpringApplication.java:306) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) at com.eric.diary.DiaryApplication.main(DiaryApplication.java:12) Caused by: org.yaml.snakeyaml.scanner.ScannerException: while scanning an alias in 'reader', line 25, column 44: ... endpoints.web.exposure.include: * ^ (13) in 'reader', line 25, column 45: ... ndpoints.web.exposure.include: * ^ at org.yaml.snakeyaml.scanner.ScannerImpl.scanAnchor(ScannerImpl.java:1444) at org.yaml.snakeyaml.scanner.ScannerImpl.fetchAlias(ScannerImpl.java:916) at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:364) at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:227) at org.yaml.snakeyaml.parser.ParserImpl$ParseBlockMappingValue.produce(ParserImpl.java:586) at org.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:158) at org.yaml.snakeyaml.parser.ParserImpl.checkEvent(ParserImpl.java:148) at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:124) at org.yaml.snakeyaml.composer.Composer.composeValueNode(Composer.java:236) at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:227) at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:215) at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:144) at org.yaml.snakeyaml.composer.Composer.getNode(Composer.java:85) at org.yaml.snakeyaml.constructor.BaseConstructor.getData(BaseConstructor.java:123) at org.yaml.snakeyaml.Yaml$1.next(Yaml.java:547) at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:161) at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:134) at org.springframework.boot.env.OriginTrackedYamlLoader.load(OriginTrackedYamlLoader.java:75) at org.springframework.boot.env.YamlPropertySourceLoader.load(YamlPropertySourceLoader.java:50) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadDocuments(ConfigFileApplicationListener.java:572) at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:526) ... 23 common frames omitted Disconnected from the target VM, address: '127.0.0.1:59532', transport: 'socket' Process finished with exit code 1
查了一些資料，發現 yml 的配置檔案的特殊符號要加上單引號，按如下配置就可以解決此問題：
management.endpoints.web.exposure.include: '*'
題外話：
配置“優雅停服”本來都快成功了，出現這個錯誤，一度以為自己又配錯了，又重新配了，耽誤了半天。其實 Spring Boot 配置的 1.x 和 2.x 配置不一樣，然後 application.properties 和 application.yml 也有一點查別。下面放出 2.1.3 的 Spring Boot “優雅停服”的配置，也算是一個記錄吧：
#/actuator轉換成/eric（你也可以寫任意的，預設是/actuator）
management.endpoints.web.base-path: /eric
#啟用所有的端點的web方式請求（也可以單獨只暴露shutdown斷點，有些人管這個叫暴露）
management.endpoints.web.exposure.include: '*'
#啟用shutdown（啟用Spring Boot的shutdown功能）
management.endpoint.shutdown.enabled: true