這兩天專案到了差不多收尾了，想把各種環境配置通過maven filter在maven打包的時候就替換掉properties的配置。之前一直用${my.properies}的方式，打包了以後就是替換不掉properties裡的屬性。
這是我的maven filter的屬性

filter.spring.freemarker.template-loader-path=file:/mnt/web/ftl/
filter.spring.resources.static-locations=file:/mnt/web/static/
filter.server.port=80
#mysql connection info
 

filter.jdbc.url=jdbc:mysql://192.168.1.111:3306/ubip?createDatabaseIfNotExist=true&useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&allowMultiQueries=true
filter.jdbc.username=root
filter.jdbc.password=banger

#redis config
filter.redis.database
 
=0
filter.redis.host=192.168.1.111
filter.redis.port=6379
filter.redis.password=1234

在application.properties檔案裡需要被替換的屬性

jdbc.url=${filter.jdbc.url}
...

maven配置

    <profiles>
        <profile>
            <id>product</id>
            <properties>
                <env
 
>product</env>
            </properties>
        </profile>
    </profiles>
    <build>
        <filters> <!-- 指定使用的 filter -->
            <filter>src/main/filters/${env}.properties</filter>
        </filters>
        <resources>
            <resource> <!-- 配置需要被替換的資原始檔路徑, properties 應該在 src/main/resource 目錄下 -->
                <directory>src/main/resources</directory>
                <excludes>
                    <exclude>static/**</exclude>
                    <exclude>ftl/**</exclude>
                </excludes>
                <filtering>true</filtering> <!-- 是否使用過濾器 -->
            </resource>
        </resources>
    </build>

以前這樣配置都是可以的。在spring boot裡就不行。後來看了官方文件，裡面有這樣一句話

13.2 Maven
Maven users can inherit from the spring-boot-starter-parent project to obtain sensible defaults. The parent project provides the following features:

Java 1.6 as the default compiler level.
UTF-8 source encoding.
A Dependency Management section, allowing you to omit tags for common dependencies, inherited from the spring-boot-dependencies POM.
Sensible resource filtering.
Sensible plugin configuration (exec plugin, surefire, Git commit ID, shade).
Sensible resource filtering for application.properties and application.yml including profile-specific files (e.g. application-foo.properties and application-foo.yml)
On the last point: since the default config files accept Spring style placeholders (${…​}) the Maven filtering is changed to use @[email protected] placeholders (you can override that with a Maven property resource.delimiter).

大致的意思是我的maven繼承了spring-boot-starter-parent，並且spring預設配置檔案接受的佔位符也是...，所以mavenfilter{}佔位符就被spring的maven pom替換掉了，變成了@[email protected]，我們可以通過resource.delimiter來覆蓋它。
看下spring-boot-starter-parent 這個pom裡寫這一段

<properties>
        <java.version>1.6</java.version>
        <resource.delimiter>@</resource.delimiter> <!-- delimiter that doesn't clash with Spring ${} placeholders -->
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <maven.compiler.source>${java.version}</maven.compiler.source>
        <maven.compiler.target>${java.version}</maven.compiler.target>
    </properties>

那一切就清楚了，我將properties中的佔位符替換下變成

#mysql connection info
jdbc.url[email protected].jdbc.url@
jdbc.username[email protected].jdbc.username@
jdbc.password[email protected].jdbc.password@

#redis config
# Redis資料庫索引（預設為0）
redis.database[email protected].redis.database@
# Redis伺服器地址
redis.host[email protected].redis.host@
# Redis伺服器連線埠
redis.port[email protected].redis.port@
# Redis伺服器連線密碼（預設為空）
redis.password[email protected].redis.password@

這樣maven就能替換屬性了。