有时候,需要将复杂的项目, 包括各种xml文件属性文件, 类, jar等等打包到一个可以执行的jar包中, 然后用java -jar xxx.jar 来运行项目, 这样简单方便, 特别是在编写一些测试工具时,尤为重要。
但是经常发现打包后的项目无法启动, 其中一大类是您项目有问题, 但是这个相对好解决, 毕竟自己的项目可以在windows下的ide中做各种调试,测试都测试好了, 在打包一般程序问题的概率就低得多了。
通过 maven-shade-plugin 生成一个 uber-jar,它包含所有的依赖 jar 包。
Goal | Description |
---|---|
shade:help | Display help information on maven-shade-plugin.Callmvn shade:help -Ddetail=true -Dgoal=<goal-name>to display parameter details. |
shade:shade | Mojo that performs shading delegating to the Shader component. |
maven-shade-plugin 将 goal shade:shade 绑定到 phase package 上。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.4.3</version> <configuration> <!-- put your configurations here --> </configuration> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> </execution> </executions> </plugin> </plugins> </build>
mvn clean package
会在 target 文件生成一个 uber-jar,以 -shaded.jar 为后缀的 jar 包。
将该工程依赖的部分 Jar 包 include/exclude 掉。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.4.3</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>
将依赖的某个 Jar 包内部的类或者资源 include/exclude 掉。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.4.3</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>
maven-shade-plugin 自动将所有不使用的类全部排除掉,将 uber-jar 最小化。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.4.3</version> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> <configuration> <minimizeJar>true</minimizeJar> </configuration> </execution> </executions> </plugin> </plugins> </build>
默认会生成一个Jar包和一个以 “-shaded”为结尾的uber-jar包,可以通过配置来指定uber-jar的后缀名。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.4.3</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>
通过设置 MainClass 创建一个可执行 Jar 包。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.4.3</version> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> <configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"> <mainClass>org.sonatype.haven.HavenCli</mainClass> </transformer> </transformers> </configuration> </execution> </executions> </plugin> </plugins> </build>
Java 工程经常会遇到第三方 Jar 包冲突,使用 maven shade plugin 解决 jar 或类的多版本冲突。 maven-shade-plugin 在打包时,可以将项目中依赖的 jar 包中的一些类文件打包到项目构建生成的 jar 包中,在打包的时候把类重命名。下面的配置将 org.codehaus.plexus.util jar 包重命名为 org.shaded.plexus.util。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.4.3</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> -----
下面的部分介绍的更为细致些, 特别是, jar包和类的剔除等
网上有一些maven-shade-plugin替代maven-assembly-plugin的文章,原因是代maven-assembly-plugin打出的jar包中要么是不能设置Main-Class,要么spring的META-INF/spring.*文件相互覆盖了。对于这两个问题,maven-assembly-plugin在当前的版本(3.1.0)中都可以解决了(方法见https://my.oschina.net/u/2377110/blog/1584205)。
实际上这两个插件所针对的用途其实是有差异的,而它们与maven默认的maven-jar-plugin都是打包插件,简单的区别如下:
|plugin|function| | — | — | |maven-jar-plugin|maven 默认打包插件,用来创建 project jar| |maven-shade-plugin|用来打可执行包,包含依赖,以及对依赖进行取舍过滤| |maven-assembly-plugin|支持定制化打包方式,更多是对项目目录的重新组装|
当你只想将项目打成一个可执行包时,maven-shade-plugin非常适合。一般情况下,pom文件中shade插件配置如下。
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>1.4</version> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> <configuration> <filters> <filter> <artifact>*:*</artifact> <excludes> <exclude>META-INF/*.SF</exclude> <exclude>META-INF/*.DSA</exclude> <exclude>META-INF/*.RSA</exclude> </excludes> </filter> </filters> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"> <mainClass>com.lcifn.Application</mainClass> </transformer> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.handlers</resource> </transformer> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.schemas</resource> </transformer> </transformers> </configuration> </execution> </executions> </plugin> </plugins> </build>
shade插件绑定的是package生命周期目标,并设置com.lcifn.Application为Main-Class,以及将META-INF/spring.*文件合并(追加而非覆盖),并过滤掉所有依赖的META/INF中SF,DSA,RSA后缀文件。这里涉及到filter配置和transformer配置。
Filter操作在打包时将jar包中的内容排除。它是以groupId:artifactId为标识,在filter内部可以使用<include>/<exclude>更细致地控制,既可以移除代码文件,也可以移除配置文件。
<!-- 按package过滤junit包 --> <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> </filters> </configuration>
如果想将整个jar包都过滤掉,可以使用<artifactSet>,也是指定groupId:artifactId的标识。
<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>
另外配置<minimizeJar>将项目中没有使用的依赖自动移除
<configuration> <minimizeJar>true</minimizeJar> </configuration>
<minimizeJar>可以和<filters>共同使用
<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>
在打包时,存在将多个构件中的class文件或资源文件聚合的需求。shade插件提供了丰富的Transformer工具类。这里介绍一些常用的Transformer。
往MANIFEST文件中写入Main-Class是可执行包的必要条件。ManifestResourceTransformer可以轻松实现。
<configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"> <mainClass>com.lcifn.Application</mainClass> </transformer> </transformers> </configuration>
用来处理多个jar包中存在重名的配置文件的合并,尤其是spring。
<configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.handlers</resource> </transformer> <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer"> <resource>META-INF/spring.schemas</resource> </transformer> </transformers> </configuration>
JDK的服务发现机制是基于META-INF/services/目录的,如果同一接口存在多个实现需要合并 ,则可以使用此Transformer。
<configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/> </transformers> </configuration>
更多的Transformer见http://maven.apache.org/plugins/maven-shade-plugin/examples/resource-transformers.html
默认情况下,shade插件会覆盖基于项目的jar包,而生成包含所有依赖的jar包。但有时需要原始的jar包和shade后的jar包同时被部署,可以配置如下。
<configuration> <shadedArtifactAttached>true</shadedArtifactAttached> <!-- 名称会作为后缀在shade构件jar包后 --> <shadedClassifierName>jackofall</shadedClassifierName> </configuration>