原文链接     译者:carvendy

模型指南

模型是一个从简单模板生成源码的工具。从简单模板你可以生成这些：

• Java源码
• XML序列化源码模型
• XML反序列化源码模型
• 模型文档
• XSD

一个经典类型模型模板如下：

<model xmlns="http://modello.codehaus.org/MODELLO/1.4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://modello.codehaus.org/MODELLO/1.4.0 http://modello.codehaus.org/xsd/modello-1.4.0.xsd"
xml.namespace="http://maven.apache.org/plugins/maven-archetype-plugin/archetype/${version}"
xml.schemaLocation="http://maven.apache.org/xsd/archetype-${version}.xsd">
<id>archetype</id>
<name>Archetype</name>
<description>
<![CDATA[Maven's model for the old archetype descriptor (ie for Archetype 1.0.x).
<p>The metadata about an archetype is stored in the <code>archetype.xml</code> file located
in the <code>META-INF/maven</code> directory of its jar file.</p>]]>
</description>
<defaults>
<default>
<key>package</key>
<value>org.apache.maven.archetype.model</value>
</default>
</defaults>
<classes>
<class rootElement="true" xml.tagName="archetype">
<name>ArchetypeModel</name>
<description>Describes the assembly layout and packaging.</description>
<version>1.0.0</version>
<fields>
<field>
<name>id</name>
<version>1.0.0</version>
<required>true</required>
<type>String</type>
<description><![CDATA[The value should be the same as the artifactId in the archetype <code>pom.xml</code>.]]></description>
</field>
<field>
<name>allowPartial</name>
<version>1.0.0</version>
<type>boolean</type>
<description><![CDATA[Setting this option to <code>true</code> makes it possible to run the
<code>archetype:create</code> even on existing projects.]]></description>
</field>
<field xdoc.separator="blank">
<name>sources</name>
<version>1.0.0</version>
<description><![CDATA[Files that will go into <code>src/main/java</code>.]]></description>
<association>
<type>Source</type>
<multiplicity>*</multiplicity>
</association>
</field>
<field>
<name>resources</name>
<version>1.0.0</version>
<description><![CDATA[Files that will go into <code>src/main/resources</code>.]]></description>
<association>
<type>Resource</type>
<multiplicity>*</multiplicity>
</association>
</field>
<field xdoc.separator="blank">
<name>testSources</name>
<version>1.0.0</version>
<description><![CDATA[Files that will go into <code>src/test/java</code>.]]></description>
<association xml.tagName="source">
<type>Source</type>
<multiplicity>*</multiplicity>
</association>
</field>
<field>
<name>testResources</name>
<version>1.0.0</version>
<description><![CDATA[Files that will go into <code>src/test/resources</code>.]]></description>
<association xml.tagName="resource">
<type>Resource</type>
<multiplicity>*</multiplicity>
</association>
</field>
<field xdoc.separator="blank">
<name>siteResources</name>
<version>1.0.0</version>
<description><![CDATA[Files that will go into <code>src/site</code>.]]></description>
<association xml.tagName="resource">
<type>Resource</type>
<multiplicity>*</multiplicity>
</association>
</field>
</fields>
</class>
<class>
<name>Source</name>
<description>Describes a source file. Note that source files are always filtered, unlike resources that
can be non-filtered.</description>
<version>1.0.0</version>
<fields>
<field xml.content="true">
<name>file</name>
<version>1.0.0</version>
<type>String</type>
<description><![CDATA[The source file.]]></description>
</field>
<field xml.attribute="true">
<name>encoding</name>
<version>1.0.0</version>
<type>String</type>
<description><![CDATA[The encoding to be used when reading/writing this file.
Platform encoding is used by default, or ISO-8859-1 when filename ends in <code>.properties</code>]]></description>
</field>
</fields>
</class>
<class>
<name>Resource</name>
<description>Describes a resource file.</description>
<version>1.0.0</version>
<fields>
<field xml.content="true">
<name>file</name>
<version>1.0.0</version>
<type>String</type>
<description><![CDATA[The resource file.]]></description>
</field>
<field xml.attribute="true">
<name>encoding</name>
<version>1.0.0</version>
<type>String</type>
<description><![CDATA[The encoding to be used when reading/writing this file.
Platform encoding is used by default, or ISO-8859-1 when filename ends in <code>.properties</code>]]></description>
</field>
<field xml.attribute="true">
<name>filtered</name>
<version>1.0.0</version>
<type>boolean</type>
<defaultValue>true</defaultValue>
<description>A resource can be filtered, which means the file will be used as Velocity template.
It can be non-filtered, which means the file will be copied without modification.</description>
</field>
</fields>
</class>
</classes>
</model>

为了利用模型你要配置maven-modello-plugin的一些东西，你想生成java源码模型，有xpp3序列化源码和xpp3反序列源码：

<project>
...
<build>
<plugins>
<plugin>
<groupId>org.codehaus.modello</groupId>
<artifactId>modello-maven-plugin</artifactId>
<version>1.8.3</version>
<executions>
<execution>
<goals>
<!-- Generate the xpp3 reader code -->
<goal>xpp3-reader</goal>
<!-- Generate the xpp3 writer code -->
<goal>xpp3-writer</goal>
<!-- Generate the Java sources for the model itself -->
<goal>java</goal>
</goals>
</execution>
</executions>
<configuration>
<models>
<model>src/main/mdo/descriptor.mdo</model>
</models>
<version>1.0.0</version>
<useJava5>true</useJava5>
</configuration>
</plugin>
</plugins>
</build>
...
</project>