Spring Boot 多模組開發-使用dependencyManagement版本管理
今天,我們來了解下如何管理和優化父專案和子模組的依賴包版本,又或者我們希望子專案B不需要全部依賴父專案A的內容,避免一股腦全部匯入。
首先,來看四個pom檔案:
1、demo-parent
<?xml version="1.0" encoding="UTF-8"?> <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.demo</groupId> <artifactId>demo-parent</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>pom</packaging> <name>demo-parent</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <modules> <module>demo-apply</module> <module>demo-common</module> <module>demo-static</module> </modules> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.1</version> <configuration> <source>${java.version}</source> <target>${java.version}</target> </configuration> </plugin> </plugins> </build> </project>
2、demo-apply
<?xml version="1.0" encoding="UTF-8"?> <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> <artifactId>demo-apply</artifactId> <packaging>jar</packaging> <name>demo-apply</name> <description>Demo project for Spring Boot</description> <parent> <groupId>com.demo</groupId> <artifactId>demo-parent</artifactId> <version>0.0.1-SNAPSHOT</version> <relativePath>../pom.xml</relativePath><!-- lookup parent from repository --> </parent> <dependencies> <!-- 加入其餘模組的依賴 --> <dependency> <groupId>com.demo</groupId> <artifactId>demo-common</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>com.demo</groupId> <artifactId>demo-static</artifactId> <version>0.0.1-SNAPSHOT</version> <type>war</type> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <!-- 當所依賴的其他模組,有啟動類的時候,需要以下配置,指定唯一啟動類, 本次事例未涉及其他模組有啟動類,可自行測試 --> <configuration> <!-- 指定該Main Class為全域性的唯一入口 --> <mainClass>com.demo.demoapply.DemoApplyApplication</mainClass> <layout>ZIP</layout> </configuration> <executions> <execution> <goals> <goal>repackage</goal><!--可以把依賴的包都打包到生成的Jar包中--> </goals> </execution> </executions> </plugin> </plugins> </build> </project>
3、demo-static
<?xml version="1.0" encoding="UTF-8"?> <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> <artifactId>demo-static</artifactId> <packaging>war</packaging> <name>demo-static</name> <description>Demo project for Spring Boot</description> <parent> <groupId>com.demo</groupId> <artifactId>demo-parent</artifactId> <version>0.0.1-SNAPSHOT</version> <relativePath>../pom.xml</relativePath><!-- lookup parent from repository --> </parent> <dependencies> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.1</version> <configuration> <source>${java.version}</source> <target>${java.version}</target> </configuration> </plugin> </plugins> </build> </project>
4、demo-common
<?xml version="1.0" encoding="UTF-8"?>
<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>
<artifactId>demo-common</artifactId>
<packaging>jar</packaging>
<name>demo-common</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>com.demo</groupId>
<artifactId>demo-parent</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../pom.xml</relativePath><!-- lookup parent from repository -->
</parent>
<dependencies>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
很明顯,我們的demo-parent為父專案,demo-apply為應用入口,demo-common放的應該是共用工具類,demo-static應該是共用的靜態檔案,如頁面等,demo-apply依賴兩者。
好,看到這裡,就有疑問了,按理來說,demo-static,存放頁面,打包成war包,應該不需要可以執行,那麼也就不需要依賴springboot的包,那麼我們進行如下改變:
demo-parent:
<?xml version="1.0" encoding="UTF-8"?>
<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.demo</groupId>
<artifactId>demo-parent</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<name>demo-parent</name>
<description>Demo project for Spring Boot</description>
<!-- 刪除 -->
<!--<parent>-->
<!--<groupId>org.springframework.boot</groupId>-->
<!--<artifactId>spring-boot-starter-parent</artifactId>-->
<!--<version>2.0.5.RELEASE</version>-->
<!--<relativePath/> <!– lookup parent from repository –>-->
<!--</parent>-->
<modules>
<module>demo-apply</module>
<module>demo-common</module>
<module>demo-static</module>
</modules>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>2.0.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.0.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>2.0.5.RELEASE</version>
<scope>test</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
demo-apply
<?xml version="1.0" encoding="UTF-8"?>
<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>
<artifactId>demo-apply</artifactId>
<packaging>jar</packaging>
<name>demo-apply</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>com.demo</groupId>
<artifactId>demo-parent</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../pom.xml</relativePath><!-- lookup parent from repository -->
</parent>
<dependencies>
<!-- 加入其餘模組的依賴 -->
<dependency>
<groupId>com.demo</groupId>
<artifactId>demo-common</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>com.demo</groupId>
<artifactId>demo-static</artifactId>
<version>0.0.1-SNAPSHOT</version>
<type>war</type>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<!-- 當所依賴的其他模組,有啟動類的時候,需要以下配置,指定唯一啟動類,
本次事例未涉及其他模組有啟動類,可自行測試 -->
<configuration>
<!-- 指定該Main Class為全域性的唯一入口 -->
<mainClass>com.demo.demoapply.DemoApplyApplication</mainClass>
<layout>ZIP</layout>
</configuration>
<executions>
<execution>
<goals>
<goal>repackage</goal><!--可以把依賴的包都打包到生成的Jar包中-->
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
大功告成,雖然這樣是OK了,大家檢視依賴發現也對,demo-static和demo-common,已經不依賴springBoot,但是有心人一定會問,demo-parent為何刪除這一段:
<!-- 刪除 -->
<!--<parent>-->
<!--<groupId>org.springframework.boot</groupId>-->
<!--<artifactId>spring-boot-starter-parent</artifactId>-->
<!--<version>2.0.5.RELEASE</version>-->
<!--<relativePath/> <!– lookup parent from repository –>-->
<!--</parent>-->
首先,告訴大家這一段從哪裡來的,idea在生成springBoot專案的時候,會採取官方建議,預設引入該父專案。
那麼問題又來了,這個父專案到底是個啥,我們預設要引入他,大家可以點選進去檢視,其實他只是個pom檔案,管理了一些預設的配置資訊,這樣才能做到,我們在預設生成專案的時候,發現我們的dependency中不需要引入版本,應為他會整合父Pom檔案的版本資訊。
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
...
</dependencies>
</dependencyManagement>
既然知道,原來是這麼回事,那我們順便查下SpringBoot的官網介紹吧,是否還有更好的方式。
果真,還有一種方式:
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>1.5.1.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
請注意,它的 type 是 pom,scope 是 import,這種型別的 dependency 只能在 dependencyManagement 標籤中宣告。
同樣我們在點進去看,原來這個POM檔案已經預設給我們使用dependencyManagement聲明瞭很多依賴,我們如果需要直接在我們的dependency中加入依賴就行,而無需指定版本。
這樣demo-parent的Pom檔案就變成了這個樣子:
<?xml version="1.0" encoding="UTF-8"?>
<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.demo</groupId>
<artifactId>demo-parent</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<name>demo-parent</name>
<description>Demo project for Spring Boot</description>
<modules>
<module>demo-apply</module>
<module>demo-common</module>
<module>demo-static</module>
</modules>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.0.0.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
這樣parent專案的POM依賴就會特別清晰。
註釋:dependencyManagement 包裹的dependencies只有宣告作用,不會實際匯入,另外關於maven中的繼承、聚合等多多瞭解,就能很好的理解上述的內容。