背景
maven是一个很好的代码构建工具，采用“约定优先于配置”的原则进行项目管理，相信很多的java开发者应该都了解maven并可能在工作当中都是通过maven来管理项目的，在创建的项目的时候，我们往往会使用maven内置的项目骨架也就是archetype来快速生成项目结构。但是在一个团队做开发的过程中，可能仅仅依靠maven预先提供的archetyp可能是不够的，团队之间协作有自己的定义方式，每个人的结构定义风格也不尽相同，在这样的背景下我们有必要去定义一个统一的代码骨架供团队使用，这样做的好处是当团队需要开始一个新项目的时候，可以利用自定义的maven骨架一键生成项目。
archetype是在maven-archetype-plugin插件执行generate目标的时候进行配置的，我们经常使用到maven的内嵌的骨架包括：maven-archetype-webapp、maven-archetype-quickstart。前者用来快速搭建一个web工程项目，后者用来快速搭建一个普通的java工程项目。
单模块项目的archetype
单模块项目的archetype脚手架项目的结构
上图中的各个文件详解：
- 根目录beast-archetype下的pom.xml和一般的maven项目一样主要定义archetype项目的坐标等信息。
- 所有的项目骨架内容都集中在src/main/resources/archetype-resources文件夹下。
- archetype-resources中的pom.xml定义了待生成项目的pom文件的内容，/src/main/java、/src/test/java中分别定义了待生成项目中相应目录下的内容
- /src/main/resources/META-INF/maven/archetype-metadata.xml中定义相关的元数据描述(其中该文件的位置固定为resources/META-INF/maven文件夹下,且名称固定为archetype-metadata.xml)。
1.beast-archetype/pom.xml内容如下1
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28<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.thebeastshop</groupId>
<artifactId>beast-archetype</artifactId>
<version>1.1</version>
<packaging>jar</packaging>
<name>beast-archetype</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>beast-archetype</finalName>
</build>
</project>
其中：上面${}标识的变量都是通过maven中的命令行传进来的，如：mvn archetype:generate -DgroupId=com.thebeastshop
2.src/main/resources/archetype-resources/pom.xml内容如下：1
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51<?xml version="1.0"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>${groupId}</groupId>
<artifactId>${artifactId}</artifactId>
<version>${version}</version>
<name>${artifactId}</name>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
</plugins>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-archetype-plugin</artifactId>
<version>2.2</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-source-plugin</artifactId>
<configuration>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
其中：上面${}标识的变量都是通过maven中的命令行传进来的，如：mvn archetype:generate -DgroupId=com.thebeastshop
3.src/main/resources/META-INF/maven/archetype-metadata.xml内容如下：1
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39<?xml version="1.0" encoding="UTF-8"?>
<archetype-descriptor name="beast-archetype"
xmlns="http://maven.apache.org/plugins/maven-archetype-plugin/archetype-descriptor/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://maven.apache.org/plugins/maven-archetype-plugin/archetype-descriptor/1.0.0
http://maven.apache.org/xsd/archetype-descriptor-1.0.0.xsd">
<requiredProperties>
<requiredProperty key="package-name" />
</requiredProperties>
<fileSets>
<fileSet filtered="true" packaged="true" encoding="UTF-8">
<directory>src/main/java</directory>
<includes>
<include>**/*.java</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8">
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" packaged="true" encoding="UTF-8">
<directory>src/test/java</directory>
<includes>
<include>**/*.java</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/test/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
</fileSets>
</archetype-descriptor>
说明：
- packaged=”true”标识src/main/resources/archetype-resources/src/main/java中对应的内容是否要放入到package中,比如package为com.thebeastshop,那么如果该属性为true,则对应的java文件会放到com/thebeastshop文件夹下，也就是包路径下。
- filtered=”true”标识下面提到的${}是否要进行替换
4.src/main/resources/archetype-resources/src/main/java/Demo.java内容如下：1
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8package ${package};
public class Demo{
public static void main( String[] args )
{
System.out.println( "Hello My Archetype!" );
}
}
5.这样我们就手写好了一个自定义的maven的archetype骨架项目，我们只需要通过mvn clean install 命令把该jar包安装到本地仓库，然后通过本地仓库中的该jar包来生成一个项目看看效果，使用如下命令：1
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6mvn archetype:generate
-DgroupId=comthebeastshop
-DartifactId=beast-test
-Dpackage="com.thebeastshop.test"
-DarchetypeGroupId=com.thebeastshop
-DarchetypeArtifactId=beast-archetype -DarchetypeVersion=1.1 -X -DarchetypeCatalog=local
多模块项目的archetype
1.多模块骨架项目的项目结构
这跟单模块项目区别不大，但是有几个概念需要说明：
- “rootArtifactId”占位符会被parent项目的artifactId替换
- ${rootArtifactId}也会被parent项目的artifactId替换
src/main/resources/archetype-resources里必须要有一个顶级pom文件（如果是单工程就是工程pom文件），同时子文件夹代表了模块定义
2.模板工程定义描述文件：META-INF/maven/archetype-metadata.xml1
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176<?xml version="1.0" encoding="UTF-8"?>
<archetype-descriptor name="beast-archetype"
xmlns="http://maven.apache.org/plugins/maven-archetype-plugin/archetype-descriptor/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://maven.apache.org/plugins/maven-archetype-plugin/archetype-descriptor/1.0.0
http://maven.apache.org/xsd/archetype-descriptor-1.0.0.xsd">
<requiredProperties>
<requiredProperty key="groupId">
<defaultValue>com.thebeastshop</defaultValue>
</requiredProperty>
<requiredProperty key="artifactId">
<defaultValue>test</defaultValue>
</requiredProperty>
<requiredProperty key="package">
<defaultValue>com.thebeastshop.test</defaultValue>
</requiredProperty>
</requiredProperties>
<modules>
<module id="${rootArtifactId}-api" name="${rootArtifactId}-api" dir="__rootArtifactId__-api">
<fileSets>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/main/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/test/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/test/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
</fileSets>
</module>
<module id="${rootArtifactId}-core" name="${rootArtifactId}-core" dir="__rootArtifactId__-core">
<fileSets>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/main/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/test/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8">
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/test/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
</fileSets>
</module>
<module id="${rootArtifactId}-dao" name="${rootArtifactId}-dao" dir="__rootArtifactId__-dao">
<fileSets>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/main/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/test/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8">
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
<include>mapper</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/test/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
</fileSets>
</module>
<module id="${rootArtifactId}-main" name="${rootArtifactId}-main" dir="__rootArtifactId__-main">
<fileSets>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/main/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/test/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8">
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/test/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/main/assembly</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/main/bin</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
</fileSets>
</module>
<module id="${rootArtifactId}-mybatisGen" name="${rootArtifactId}-mybatisGen" dir="__rootArtifactId__-mybatisGen">
<fileSets>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/main/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet filtered="true" encoding="UTF-8" packaged="true">
<directory>src/test/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
<fileSet encoding="UTF-8">
<directory>src/test/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</fileSet>
</fileSets>
</module>
</modules>
</archetype-descriptor>属性变量定义,这些属性可以在资源元文件里的任意一个文件里通过${var}来引用，所以的元文件最终都可以选择通过velocity引擎来执行替换后生成。默认的属性有：groupId，artifactId，packeage，version等