maven filter不起作用

遇到的一个坑， spring boot + maven maven fileter没有起作用。spring boot把默认占位符改了

参考：https://blog.csdn.net/mn960mn/article/details/78834875

创建一个maven项目，项目结构如下：

其中，pom.xml的内容如下：

1.  
   <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
2.  
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
3.  
   <modelVersion>4.0.0</modelVersion>
4.  
    
5.  
   <groupId>com.pp.test</groupId>
6.  
   <artifactId>properties-test</artifactId>
7.  
   <version>0.0.1-SNAPSHOT</version>
8.  
   <packaging>jar</packaging>
9.  
    
10.  
    <name>properties-test</name>
11.  
    <url>http://maven.apache.org</url>
12.  
     
13.  
    <parent>
14.  
    <groupId>org.springframework.boot</groupId>
15.  
    <artifactId>spring-boot-starter-parent</artifactId>
16.  
    <version>1.5.9.RELEASE</version>
17.  
    </parent>
18.  
     
19.  
    <properties>
20.  
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
21.  
    <maven.compiler.source>1.8</maven.compiler.source>
22.  
    <maven.compiler.target>1.8</maven.compiler.target>
23.  
    <java.version>1.8</java.version>
24.  
    </properties>
25.  
     
26.  
    <dependencies>
27.  
    <dependency>
28.  
    <groupId>org.springframework.boot</groupId>
29.  
    <artifactId>spring-boot-starter-web</artifactId>
30.  
    </dependency>
31.  
    </dependencies>
32.  
     
33.  
    <build>
34.  
    <filters>
35.  
    <filter>src/main/profiles/profile-${profiles.active}.properties</filter>
36.  
    </filters>
37.  
    <resources>
38.  
    <resource>
39.  
    <filtering>true</filtering>
40.  
    <directory>src/main/resources</directory>
41.  
    </resource>
42.  
    </resources>
43.  
    </build>
44.  
     
45.  
     
46.  
    <profiles>
47.  
    <profile>
48.  
    <id>dev</id>
49.  
    <properties>
50.  
    <profiles.active>dev</profiles.active>
51.  
    </properties>
52.  
    <activation>
53.  
    <activeByDefault>true</activeByDefault>
54.  
    </activation>
55.  
    </profile>
56.  
    <profile>
57.  
    <id>test</id>
58.  
    <properties>
59.  
    <profiles.active>test</profiles.active>
60.  
    </properties>
61.  
    </profile>
62.  
    <profile>
63.  
    <id>prod</id>
64.  
    <properties>
65.  
    <profiles.active>prod</profiles.active>
66.  
    </properties>
67.  
    </profile>
68.  
    </profiles>
69.  
    </project>

application.properties 文件内容：

1.  
   jdbc.driverClassName=${jdbc.driverClassName}
2.  
   jdbc.url=${jdbc.url}
3.  
   jdbc.username=${jdbc.username}
4.  
   jdbc.password=${jdbc.password}

profile-dev.properties 文件内容：

1.  
   jdbc.driverClassName=com.mysql.jdbc.Driver
2.  
   jdbc.url=jdbc:mysql:///db_users
3.  
   jdbc.username=root
4.  
   jdbc.password=root

启动应用，报错了，错误如下：

1.  
   Caused by: java.lang.IllegalArgumentException: Circular placeholder reference 'jdbc.url' in property definitions
2.  
   at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:141) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
3.  
   at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:162) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
4.  
   at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
5.  
   at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:236) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
6.  
   at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
7.  
   at org.springframework.core.env.AbstractPropertyResolver.resolveNestedPlaceholders(AbstractPropertyResolver.java:227) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
8.  
   at org.springframework.core.env.PropertySourcesPropertyResolver.getProperty(PropertySourcesPropertyResolver.java:84) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
9.  
   at org.springframework.core.env.PropertySourcesPropertyResolver.getProperty(PropertySourcesPropertyResolver.java:61) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
10.  
    at org.springframework.core.env.AbstractEnvironment.getProperty(AbstractEnvironment.java:527) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
11.  
    at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$1.getProperty(PropertySourcesPlaceholderConfigurer.java:132) ~[spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]
12.  
    at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$1.getProperty(PropertySourcesPlaceholderConfigurer.java:129) ~[spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]
13.  
    at org.springframework.core.env.PropertySourcesPropertyResolver.getProperty(PropertySourcesPropertyResolver.java:81) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
14.  
    at org.springframework.core.env.PropertySourcesPropertyResolver.getPropertyAsRawString(PropertySourcesPropertyResolver.java:71) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
15.  
    at org.springframework.core.env.AbstractPropertyResolver$1.resolvePlaceholder(AbstractPropertyResolver.java:239) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
16.  
    at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:147) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
17.  
    at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
18.  
    at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:236) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
19.  
    at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210) ~[spring-core-4.3.13.RELEASE.jar:4.3.13.RELEASE]
20.  
    at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$2.resolveStringValue(PropertySourcesPlaceholderConfigurer.java:172) ~[spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]
21.  
    at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:831) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
22.  
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1086) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
23.  
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
24.  
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
25.  
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
26.  
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]
27.  
    ... 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

1.  
   <parent>
2.  
   <groupId>org.springframework.boot</groupId>
3.  
   <artifactId>spring-boot-starter-parent</artifactId>
4.  
   <version>1.5.9.RELEASE</version>
5.  
   </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

1.  
   <properties>
2.  
   <resource.delimiter>${}</resource.delimiter>
3.  
   </properties>

方法二：

application.properties里面不用${}，改成@

1.  
   jdbc.driverClassName=@jdbc.driverClassName@
2.  
   jdbc.url=@jdbc.url@
3.  
   jdbc.username=@jdbc.username@
4.  
   jdbc.password=@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

1.  
   <parent>
2.  
   <groupId>org.springframework.boot</groupId>
3.  
   <artifactId>spring-boot-starter-parent</artifactId>
4.  
   <version>1.5.9.RELEASE</version>
5.  
   </parent>

改成

1.  
   <dependencyManagement>
2.  
   <dependencies>
3.  
   <dependency>
4.  
   <groupId>org.springframework.boot</groupId>
5.  
   <artifactId>spring-boot-starter-web</artifactId>
6.  
   <version>1.5.9.RELEASE</version>
7.  
   <type>pom</type>
8.  
   <scope>import</scope>
9.  
   </dependency>
10.  
    </dependencies>
11.  
    </dependencyManagement>