maven项目引入spring boot依赖之后filter不生效的问题

创建一个maven项目，项目结构如下：

其中，pom.xml的内容如下：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.pp.test</groupId><artifactId>properties-test</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>properties-test</name><url>http://maven.apache.org</url><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.9.RELEASE</version></parent><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target><java.version>1.8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency></dependencies><build><filters><filter>src/main/profiles/profile-${profiles.active}.properties</filter></filters><resources><resource><filtering>true</filtering><directory>src/main/resources</directory></resource></resources></build><profiles><profile><id>dev</id><properties><profiles.active>dev</profiles.active></properties><activation><activeByDefault>true</activeByDefault></activation></profile><profile><id>test</id><properties><profiles.active>test</profiles.active></properties></profile><profile><id>prod</id><properties><profiles.active>prod</profiles.active></properties></profile></profiles></project>

application.properties 文件内容：

jdbc.driverClassName=${jdbc.driverClassName}jdbc.url=${jdbc.url}jdbc.username=${jdbc.username}jdbc.password=${jdbc.password}

profile-dev.properties 文件内容：

jdbc.driverClassName=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql:///db_usersjdbc.username=rootjdbc.password=root

启动应用，报错了，错误如下：

Caused by: java.lang.IllegalArgumentException: Circular placeholder reference 'jdbc.url' in property definitionsat org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:141) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:162) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:236) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.AbstractPropertyResolver.resolveNestedPlaceholders(AbstractPropertyResolver.java:227) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.PropertySourcesPropertyResolver.getProperty(PropertySourcesPropertyResolver.java:84) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.PropertySourcesPropertyResolver.getProperty(PropertySourcesPropertyResolver.java:61) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.AbstractEnvironment.getProperty(AbstractEnvironment.java:527) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$1.getProperty(PropertySourcesPlaceholderConfigurer.java:132) ~[spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$1.getProperty(PropertySourcesPlaceholderConfigurer.java:129) ~[spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.PropertySourcesPropertyResolver.getProperty(PropertySourcesPropertyResolver.java:81) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.PropertySourcesPropertyResolver.getPropertyAsRawString(PropertySourcesPropertyResolver.java:71) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.AbstractPropertyResolver$1.resolvePlaceholder(AbstractPropertyResolver.java:239) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:147) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:236) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$2.resolveStringValue(PropertySourcesPlaceholderConfigurer.java:172) ~[spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:831) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1086) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]... 17 common frames omitted

报这个错误的原因是，maven的filtering没有起作用，没有把占位符给替换掉。（大家可以执行mvn clean package，看看打包后的jar里面的application.properties文件，是否有替换占位符）

filtering无效的原因是，pom.xml继承了spring boot的依赖

<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.9.RELEASE</version></parent>

点开这个依赖的pom.xml，我们发现

spring boot把默认的占位符号${}改成了@

找到原因了，那怎么解决就很简单了。

方法一：

在pom.xml里面添加如下内容

<properties><resource.delimiter>${}</resource.delimiter></properties>

方法二：

application.properties里面不用${}，改成@

jdbc.driverClassName=@[e-mail]=@[e-mail]=@[e-mail]=@jdbc.password@

方法三：

pom.xml不继承spring-boot-starter-parent，dependency里面配置全部的依赖和版本号（继承了之后，很多依赖不用写version）

方法四：

把

<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.9.RELEASE</version></parent>

改成

<dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId><version>1.5.9.RELEASE</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement>