1. Selecting Contents for Uber JAR
下面的POM代码段显示了如何控制在uber JAR中应该包含/排除哪些项目依赖关系:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<artifactSet>
<excludes>
<exclude>classworlds:classworlds</exclude>
<exclude>junit:junit</exclude>
<exclude>jmock:*</exclude>
<exclude>*:xml-apis</exclude>
<exclude>org.apache.maven:lib:tests</exclude>
<exclude>log4j:log4j:jar:</exclude>
</excludes>
</artifactSet>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
当然,也可以使用<includes>
来指定组件的白名单。组件形式由groupId:artifactId[[:type]:classifier]
的复合标识符表示。从插件1.3版本开始,通配符'*'和'?'可以用来做全局模式匹配。对于包含所选依赖关系的那些类的细粒度控制,可以使用组件过滤器:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<filters>
<filter>
<artifact>junit:junit</artifact>
<includes>
<include>junit/framework/**</include>
<include>org/junit/**</include>
</includes>
<excludes>
<exclude>org/junit/experimental/**</exclude>
<exclude>org/junit/runners/**</exclude>
</excludes>
</filter>
<filter>
<artifact>*:*</artifact>
<excludes>
<exclude>META-INF/*.SF</exclude>
<exclude>META-INF/*.DSA</exclude>
<exclude>META-INF/*.RSA</exclude>
</excludes>
</filter>
</filters>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
这里,类似Ant的模式用于指定依赖关系junit:junit
中只有某些类/资源应该包含在uber JAR中。第二个过滤器演示了插件1.3版中引入的组件身份(artifact identity)通配符的使用。它从每个组件排除所有与签名相关的文件,而不管其组是什么或工件ID是什么。
除了用户指定的过滤器之外,插件还可以配置为自动删除项目未使用的所有依赖关系类,从而最大限度地减少所产生的JAR:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<minimizeJar>true</minimizeJar>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
从版本1.6开始,minimizeJar将respect由过滤器中include
标记的类。 请注意,为组件中的类显示指定include过滤器会隐式排除该组件中的其他所有非指定类:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<minimizeJar>true</minimizeJar>
<filters>
<filter>
<artifact>log4j:log4j</artifact>
<includes>
<include>**</include>
</includes>
</filter>
<filter>
<artifact>commons-logging:commons-logging</artifact>
<includes>
<include>**</include>
</includes>
</filter>
</filters>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
2. 重定位类 Relocating Classes
如果uber JAR被重用为某个其他项目的依赖,如果直接包含所有来自uber JAR中组件的依赖可能会导致类加载冲突,这是由于在classpath上有重复类。为了解决这个问题,可以重新定位包含在阴影组件(shaded artifact)中的类,以创建其字节码的私有副本:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<relocations>
<relocation>
<pattern>org.codehaus.plexus.util</pattern>
<shadedPattern>org.shaded.plexus.util</shadedPattern>
<excludes>
<exclude>org.codehaus.plexus.util.xml.Xpp3Dom</exclude>
<exclude>org.codehaus.plexus.util.xml.pull.*</exclude>
</excludes>
</relocation>
</relocations>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
这指示插件通过移动相应的JAR文件条目并重写受影响的字节码( JAR file entries and rewritting the affected bytecode),将org.codehaus.plexus.util包以及子包中的类从组件org.shaded.plexus.util
中移到org.shaded.plexus.util
包中。Xpp3Dom类和pull其他类将保留在原始包中。
3. Attaching the Shaded Artifact
默认情况下,插件将用阴影组件替换项目的主要组件。如果原始和阴影的组件都应该安装/部署到存储库中,那么可以配置插件使阴影工件附加为辅助工件:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<shadedArtifactAttached>true</shadedArtifactAttached>
<shadedClassifierName>jackofall</shadedClassifierName> <!-- Any name that makes sense -->
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
通过附加的分类器将阴影组件与主要组件区分开来。
原文:http://maven.apache.org/plugins/maven-shade-plugin/examples/includes-excludes.html
http://maven.apache.org/plugins/maven-shade-plugin/examples/class-relocation.html
http://maven.apache.org/plugins/maven-shade-plugin/examples/attached-artifact.html