背景
SpringBoot 的 yml 文件中使用了 Maven pom.xml 中的 properties ：
<properties>
<active>dev</active>
</properties>
这些 properties 预期是在 mvn compile 阶段将类似 @active@ 的占位符内容替换掉：
spring:
profiles:
active: @active@
如果成功替换，在 target 目录下的 yml 文件中能看到占位符被替换为 pom.xml 中对应的值，且项目能正常启动：
spring:
profiles:
active: dev
如果有问题，则会在启动时报错：
org.springframework.boot.SpringApplication - Application run failed
org.yaml.snakeyaml.scanner.ScannerException: while scanning for the next token
found character '@' that cannot start any token. (Do not use @ for indentation)
in 'reader', line 5, column 13:
active: @active@
^
at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:439)
at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:248)
at org.yaml.snakeyaml.parser.ParserImpl$ParseBlockMappingValue.produce(ParserImpl.java:665)
at org.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:165)
at org.yaml.snakeyaml.comments.CommentEventsCollector$1.peek(CommentEventsCollector.java:59)
at org.yaml.snakeyaml.comments.CommentEventsCollector$1.peek(CommentEventsCollector.java:45)
at org.yaml.snakeyaml.comments.CommentEventsCollector.collectEvents(CommentEventsCollector.java:140)
at org.yaml.snakeyaml.comments.CommentEventsCollector.collectEvents(CommentEventsCollector.java:119)
at org.yaml.snakeyaml.composer.Composer.composeScalarNode(Composer.java:214)
at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:184)
at org.yaml.snakeyaml.composer.Composer.composeKeyNode(Composer.java:310)
at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:301)
at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:286)
at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:188)
at org.yaml.snakeyaml.composer.Composer.composeValueNode(Composer.java:314)
at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:305)
at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:286)
at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:188)
at org.yaml.snakeyaml.composer.Composer.composeValueNode(Composer.java:314)
at org.yaml.snakeyaml.composer.Composer.composeMappingChildren(Composer.java:305)
at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:286)
at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:188)
at org.yaml.snakeyaml.composer.Composer.getNode(Composer.java:115)
at org.yaml.snakeyaml.constructor.BaseConstructor.getData(BaseConstructor.java:135)
at org.springframework.boot.env.OriginTrackedYamlLoader$OriginTrackingConstructor.getData(OriginTrackedYamlLoader.java:99)
at org.yaml.snakeyaml.Yaml$1.next(Yaml.java:514)
at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:198)
at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:166)
at org.springframework.boot.env.OriginTrackedYamlLoader.load(OriginTrackedYamlLoader.java:84)
at org.springframework.boot.env.YamlPropertySourceLoader.load(YamlPropertySourceLoader.java:50)
at org.springframework.boot.context.config.StandardConfigDataLoader.load(StandardConfigDataLoader.java:54)
at org.springframework.boot.context.config.StandardConfigDataLoader.load(StandardConfigDataLoader.java:36)
at org.springframework.boot.context.config.ConfigDataLoaders.load(ConfigDataLoaders.java:107)
at org.springframework.boot.context.config.ConfigDataImporter.load(ConfigDataImporter.java:128)
at org.springframework.boot.context.config.ConfigDataImporter.resolveAndLoad(ConfigDataImporter.java:86)
at org.springframework.boot.context.config.ConfigDataEnvironmentContributors.withProcessedImports(ConfigDataEnvironmentContributors.java:116)
at org.springframework.boot.context.config.ConfigDataEnvironment.processInitial(ConfigDataEnvironment.java:240)
at org.springframework.boot.context.config.ConfigDataEnvironment.processAndApply(ConfigDataEnvironment.java:227)
at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:102)
at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:94)
at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEnvironmentPreparedEvent(EnvironmentPostProcessorApplicationListener.java:102)
at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEvent(EnvironmentPostProcessorApplicationListener.java:87)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:176)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:169)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:143)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:131)
at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:85)
at org.springframework.boot.SpringApplicationRunListeners.lambda$environmentPrepared$2(SpringApplicationRunListeners.java:66)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:120)
at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:114)
at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:65)
at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:338)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:296)
at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:164)
at org.springframework.cloud.bootstrap.BootstrapApplicationListener.bootstrapServiceContext(BootstrapApplicationListener.java:195)
at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:114)
at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:77)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:176)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:169)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:143)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:131)
at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:85)
at org.springframework.boot.SpringApplicationRunListeners.lambda$environmentPrepared$2(SpringApplicationRunListeners.java:66)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:120)
at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:114)
at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:65)
at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:338)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:296)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292)
解决办法
在对应的 pom.xml 中添加下列配置：
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
</build>