Maven多模塊項目，統一使用父pom的依賴

當前項目是一個平台，為了好管理，需要區分多個子系統，所以需要創建一個Maven多模塊項目。

框架使用的是SpringBoot，其中用到的starter包有：

1. lombok
2. validation
3. mybatis-plus
4. mysql驅動
5. devtools

為了好管理，所以將父pom進行改造：

一共有這么幾步：

首先引入parent，為的是統一starter的版本：

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.6.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<groupId>com.example.child.demo</groupId>
<artifactId>business-child-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>

然后需要將packaging修改為pom

<packaging>pom</packaging>

指定編譯插件和release插件

<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>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-release-plugin</artifactId>
            <version>2.4.1</version>
            <configuration>
                <autoVersionSubmodules>true</autoVersionSubmodules>
            </configuration>
        </plugin>
    </plugins>
</build>

然后引入需要的依賴：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-validation</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>${mybatis-plus.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

然后在子項目的pom.xml中通過parent引入父pom.xml

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example.child.demo</groupId>
    <artifactId>business-child-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>business-child-demo</name>
    <description>Spring Boot Demo</description>

    <parent>
        <groupId>org.example.parent</groupId>
        <artifactId>example-parent</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

這樣就可以了，然后就可以通過package命令打成jar包運行了。