1. 引言
备注：本文的代码都提交到了码云，有兴趣的童鞋可以clone参阅，地址：https://gitee.com/19931024/microservice-framework
本文目录结构：
|_ _ 1.引言
|_ _ _ _ _ 2.项目根节点
|_ _ _ _ _ _ _ 2.1 基础配置
|_ _ _ _ _ _ _ _ _ 2.1.1 packaging方式
|_ _ _ _ _ _ _ 2.2 properties配置
|_ _ _ _ _ _ _ 2.3 dependency配置
|_ _ _ _ _ _ _ 2.4 build配置
|_ _ _ _ _ _ _ 2.5 repositories配置
|_ _ _ _ _ _ _ 2.6 distributionManagement配置
|_ _ _ _ _ _ _ 2.7 developers配置
《轮子项目》前面前53篇文章都是描写理论的，本文回归本质，从代码开始讲起。
基本所有Java后台的项目都是使用Maven来构建的，本文主要讲解《轮子项目》的根节点管理。
2. 项目根节点
先贴上项目根节点的pom内容：
<?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.ylw</groupId>
<artifactId>central-parent</artifactId>
<version>1.0.0</version>
<packaging>pom</packaging>
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>8</java.version>
<spring-cloud-alibaba-dependencies.version>2.2.5.RELEASE</spring-cloud-alibaba-dependencies.version>
<spring-boot-dependencies.version>2.3.8.RELEASE</spring-boot-dependencies.version>
<spring-cloud-dependencies.version>Hoxton.SR9</spring-cloud-dependencies.version>
<commons-collections4.version>4.4</commons-collections4.version>
<swagger.version>2.9.2</swagger.version>
<swagger.ui.version>1.8.7</swagger.ui.version>
<swagger.mg.ui.version>1.0.6</swagger.mg.ui.version>
<swagger.butler.version>2.0.1</swagger.butler.version>
<jjwt.version>0.9.1</jjwt.version>
<druid-starter>1.1.22</druid-starter>
<jasypt.version>1.14</jasypt.version>
<sharding-sphere.version>3.1.0</sharding-sphere.version>
<security-oauth2.version>2.3.8.RELEASE</security-oauth2.version>
<security-jwt.version>1.1.0.RELEASE</security-jwt.version>
<redisson-starter.version>3.14.1</redisson-starter.version>
<easyCaptcha.version>1.6.2</easyCaptcha.version>
<hutool.version>5.1.4</hutool.version>
<mybatis-plus-boot-starter.version>3.4.0</mybatis-plus-boot-starter.version>
<aliyun-sdk-oss>3.8.1</aliyun-sdk-oss>
<qiniu-java-sdk>7.2.28</qiniu-java-sdk>
<easypoi.version>4.1.3</easypoi.version>
<poi.version>4.1.1</poi.version>
<spring-boot-admin.version>2.3.1</spring-boot-admin.version>
<velocity.version>1.7</velocity.version>
<commons-configuration2.version>2.7</commons-configuration2.version>
<txlcn.version>5.0.2.RELEASE</txlcn.version>
<fastdfs-client.version>1.27.2</fastdfs-client.version>
<userAgent.version>1.21</userAgent.version>
<transmittable.version>2.12.0</transmittable.version>
<banner.version>1.0.2</banner.version>
<commons-beanutils.version>1.9.4</commons-beanutils.version>
<spring-social-security.version>1.1.6.RELEASE</spring-social-security.version>
<commons-io.version>2.6</commons-io.version>
<servlet-api.version>4.0.1</servlet-api.version>
<spring-data-elasticsearch.version>4.1.3</spring-data-elasticsearch.version>
<elasticsearch.version>7.10.2</elasticsearch.version>
<knife4j.version>2.0.5</knife4j.version>
<hibernate-validator.version>6.2.0.Final</hibernate-validator.version>
<dubbo.version>2.7.8</dubbo.version>
<docker-maven-plugin.version>1.2.2</docker-maven-plugin.version>
<sonar.exclusions>ylw-job/**/*, ylw-register/**/*, ylw-web/**/*</sonar.exclusions>
<docker.baseImage>openjdk:8-jre-alpine</docker.baseImage>
<docker.volumes>/tmp</docker.volumes>
<docker.image.prefix>hub.ylw.com:8080/microservices-platform</docker.image.prefix>
<docker.java.security.egd>-Djava.security.egd=file:/dev/./urandom</docker.java.security.egd>
<docker.java.opts>-Xms128m -Xmx128m</docker.java.opts>
</properties>
<dependencyManagement>
<dependencies>
<!-- druid 官方 starter -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>${druid-starter}</version>
</dependency>
<!-- mybatis-plus start -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>${mybatis-plus-boot-starter.version}</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-extension</artifactId>
<version>${mybatis-plus-boot-starter.version}</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus</artifactId>
<version>${mybatis-plus-boot-starter.version}</version>
</dependency>
<!-- 加入spring security spring security oauth2的处理 -->
<dependency>
<groupId>org.springframework.security.oauth</groupId>
<artifactId>spring-security-oauth2</artifactId>
<version>${security-oauth2.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-jwt</artifactId>
<version>${security-jwt.version}</version>
</dependency>
<!-- 在Redis基础上的一个Java实用工具包 -->
<dependency>
<groupId>org.redisson</groupId>
<artifactId>redisson-spring-boot-starter</artifactId>
<version>${redisson-starter.version}</version>
</dependency>
<!-- swagger -->
<dependency>
<groupId>com.github.zlt2000</groupId>
<artifactId>swagger-butler-core</artifactId>
<version>${swagger.butler.version}</version>
</dependency>
<!-- 验证码生成工具 -->
<dependency>
<groupId>com.github.whvcse</groupId>
<artifactId>easy-captcha</artifactId>
<version>${easyCaptcha.version}</version>
</dependency>
<!-- hutool java工具类库 -->
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>${hutool.version}</version>
</dependency>
<dependency>
<groupId>com.aliyun.oss</groupId>
<artifactId>aliyun-sdk-oss</artifactId>
<version>${aliyun-sdk-oss}</version>
</dependency>
<!-- 七牛依赖 -->
<dependency>
<groupId>com.qiniu</groupId>
<artifactId>qiniu-java-sdk</artifactId>
<version>${qiniu-java-sdk}</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>${poi.version}</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>${poi.version}</version>
</dependency>
<!-- easypoi -->
<dependency>
<groupId>cn.afterturn</groupId>
<artifactId>easypoi-base</artifactId>
<version>${easypoi.version}</version>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-server</artifactId>
<version>${spring-boot-admin.version}</version>
</dependency>
<dependency>
<groupId>org.apache.velocity</groupId>
<artifactId>velocity</artifactId>
<version>${velocity.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-configuration2</artifactId>
<version>${commons-configuration2.version}</version>
</dependency>
<dependency>
<groupId>com.codingapi.txlcn</groupId>
<artifactId>txlcn-tm</artifactId>
<version>${txlcn.version}</version>
</dependency>
<dependency>
<groupId>com.codingapi.txlcn</groupId>
<artifactId>txlcn-tc</artifactId>
<version>${txlcn.version}</version>
</dependency>
<dependency>
<groupId>com.codingapi.txlcn</groupId>
<artifactId>txlcn-txmsg-netty</artifactId>
<version>${txlcn.version}</version>
</dependency>
<dependency>
<groupId>io.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>${sharding-sphere.version}</version>
</dependency>
<dependency>
<groupId>com.github.tobato</groupId>
<artifactId>fastdfs-client</artifactId>
<version>${fastdfs-client.version}</version>
</dependency>
<dependency>
<groupId>eu.bitwalker</groupId>
<artifactId>UserAgentUtils</artifactId>
<version>${userAgent.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>transmittable-thread-local</artifactId>
<version>${transmittable.version}</version>
</dependency>
<dependency>
<groupId>com.nepxion</groupId>
<artifactId>banner</artifactId>
<version>${banner.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.social</groupId>
<artifactId>spring-social-security</artifactId>
<version>${spring-social-security.version}</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>${commons-io.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>${servlet-api.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-elasticsearch</artifactId>
<version>${spring-data-elasticsearch.version}</version>
</dependency>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>${elasticsearch.version}</version>
</dependency>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-client</artifactId>
<version>${elasticsearch.version}</version>
</dependency>
<dependency>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>${elasticsearch.version}</version>
</dependency>
<dependency>
<groupId>com.github.xiaoymin</groupId>
<artifactId>knife4j-spring-boot-starter</artifactId>
<version>${knife4j.version}</version>
</dependency>
<dependency>
<groupId>com.github.xiaoymin</groupId>
<artifactId>knife4j-micro-spring-boot-starter</artifactId>
<version>${knife4j.version}</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>${hibernate-validator.version}</version>
</dependency>
<dependency>
<groupId>org.apache.dubbo</groupId>
<artifactId>dubbo</artifactId>
<version>${dubbo.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${spring-boot-dependencies.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud-dependencies.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-alibaba-dependencies</artifactId>
<version>${spring-cloud-alibaba-dependencies.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-collections4</artifactId>
<version>${commons-collections4.version}</version>
</dependency>
<dependency>
<groupId>commons-beanutils</groupId>
<artifactId>commons-beanutils</artifactId>
<version>${commons-beanutils.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot-dependencies.version}</version>
</plugin>
<plugin>
<groupId>com.spotify</groupId>
<artifactId>docker-maven-plugin</artifactId>
<version>${docker-maven-plugin.version}</version>
</plugin>
</plugins>
</pluginManagement>
</build>
<repositories>
<repository>
<id>aliyun-repos</id>
<url>https://maven.aliyun.com/repository/public</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<distributionManagement>
<repository>
<id>releases</id>
<name>releases Repository</name>
<url>http://192.168.28.138:8081/repository/maven-releases/</url>
</repository>
<snapshotRepository>
<id>snapshots</id>
<url>http://192.168.28.138:8081/repository/maven-snapshots/</url>
<uniqueVersion>true</uniqueVersion>
</snapshotRepository>
</distributionManagement>
<developers>
<developer>
<name>LinWei YangLinwei</name>
<organizationUrl>https://gitee.com/19931024/microservice-framework</organizationUrl>
<url>https://yanglinwei.blog.csdn.net/</url>
</developer>
</developers>
</project>
很多内容对吧！我上面的一串可以不看，我把代码折叠后，如下图：
主要分为如下几块：
- 根节点的版本、描述、id、组织id定义
- properties版本号统一管理
- dependencyManagement依赖管理
- dependencies 公用依赖管理
- build
- repositories
- distributionManagement
- developers
下面来详解。
2.1 基础配置
解析：
- modelVersion：指定了当前POM模型的版本，对于Maven2及Maven 3来说，它只能是4.0.0；
- groupId：项目组织唯一的标识符，实际对应JAVA的包的结构，是main目录里java的目录结构；
- artifactId：就是项目的唯一的标识符，实际对应项目的名称，就是项目根目录的名称；
- description：描述
- version：版本号
- packaging：分为pom、jar、war下面继续讲解
2.1.1 packaging方式
packaging默认是jar类型，有几种打包方式：
- pom：父类型都为pom类型
- jar：内部调用或者是作服务使用
- war：需要部署的项目
2.2 properties配置
通过properties元素用户可以自定义一个或多个Maven属性，然后在POM的其它地方使用**${属性名}**的方式引用该属性。
这种做法的最大意义在于消除重复和统一管理。
2.3 dependency配置
| dependencyManagement | dependencies |
|---|---|
 |
 |
描述：
- dependencyManagement：dependencyManagement里只是声明依赖，并不实现引入，因此子项目需要显示的声明需要用的依赖。如果不在子项目中声明依赖，是不会从父项目中继承下来的；只有在子项目中写了该依赖项，并且没有指定具体版本，才会从父项目中继承该项，并且version和scope都读取自父pom;另外如果子项目中指定了版本号，那么会使用子项目中指定的jar版本。
- dependencies：即使在子项目中不写该依赖项，那么子项目仍然会从父项目中继承该依赖项（全部继承）
2.4 build配置
和前面说的dependencies 和 dependencyManagement 的区别是非常类似的
描述：
- plugins：plugins 下的 plugin 是真实使用的
- pluginManagement ：pluginManagement 下的 plugins 下的plugin则仅仅是一种声明，子项目中可以对pluginManagement 下的 plugin 进行信息的选择、继承、覆盖等。
2.5 repositories配置
描述：
- repositories标签的作用是用来配置maven项目的远程仓库；
- 可以在repositories下面添加多个repository；
- 每个repository都有它唯一的ID，一个描述性的name，以及最重要的，远程仓库的url；
- <releases><enabled>true</enabled></releases>告诉Maven可以从这个仓库下载releases版本的构件，而<snapshots><enabled>false</enabled></snapshots>告诉Maven不要从这个仓库下载snapshot版本的构件（禁止从公共仓库下载snapshot构件是推荐的做法，因为这些构件不稳定，且不受你控制，你应该避免使用。当然，如果你想使用局域网内组织内部的仓库，你可以激活snapshot的支持）。
2.6 distributionManagement配置
描述：
- mvn install 会将项目生成的构件安装到本地Maven仓库；
- mvn deploy 用来将项目生成的构件分发到远程Maven仓库；
- distributionManagement的作用是来指定Maven分发构件的位置。
- snapshot为开发过程中的版本，实时，但不稳定，release版本则比较稳定
- Maven会根据你项目的版本来判断将构件分发到哪个仓库
2.7 developers配置
描述：用来声明一些开发者的信息
