Maven 程序集 - 读取程序集时出错

Question

我已经定义了一个个性化的 jar-with-dependencies 程序集描述符。但是，当我使用 mvn assembly:assembly 执行它时，我得到：

...
[INFO] META-INF/ already added, skipping
[INFO] META-INF/MANIFEST.MF already added, skipping
[INFO] javax/ already added, skipping
[INFO] META-INF/ already added, skipping
[INFO] META-INF/MANIFEST.MF already added, skipping
[INFO] META-INF/maven/ already added, skipping
[INFO] [assembly:assembly {execution: default-cli}]
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Error reading assemblies: No assembly descriptors found.

我的 jar-with-dependencies.xml 位于 src/main/resources/assemblies/。

我的程序集描述符如下：

<?xml version='1.0' encoding='UTF-8'?>
<assembly>
    <id>jar-with-dependencies</id>
    <formats>
        <format>jar</format>
    </formats>

    <dependencySets>
        <dependencySet>
            <scope>runtime</scope>
            <unpack>true</unpack>
            <unpackOptions>
                <excludes>
                    <exclude>**/LICENSE*</exclude>
                    <exclude>**/README*</exclude>
                </excludes>
            </unpackOptions>
        </dependencySet>
    </dependencySets>

    <fileSets>
        <fileSet>
            <directory>${project.build.outputDirectory}</directory>
            <outputDirectory>/</outputDirectory>
        </fileSet>
        <fileSet>
            <directory>src/main/resources/META-INF/services</directory>
            <outputDirectory>META-INF/services</outputDirectory>
        </fileSet>
    </fileSets>

</assembly>

而我的项目 pom.xml 是：

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-assembly-plugin</artifactId>
    <version>2.2-beta-5</version>
    <executions>
        <execution>
            <id>jar-with-dependencies</id>
            <phase>package</phase>
            <goals>
                <goal>single</goal>
            </goals>
            <configuration>
                <descriptors>
                    <descriptor>jar-with-dependencies.xml</descriptor>
                </descriptors>
                <archive>
                    <manifest>
                        <mainClass>org.my.app.HowTo</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </execution>
    </executions>
</plugin>

执行 mvn assembly:assembly 时，解包依赖项，解包完成后出现上一个错误。

此外，如果我执行 mvn -e assembly:assembly 表示没有找到描述符，但是它会尝试解压缩依赖项并创建一个具有依赖项的 JAR，但它不包含 META-INF/services/*在描述符中指定：

[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Error reading assemblies: No assembly descriptors found.

[INFO] ------------------------------------------------------------------------
[INFO] Trace
org.apache.maven.lifecycle.LifecycleExecutionException: Error reading assemblies: No assembly descriptors found.
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:719)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeStandaloneGoal(DefaultLifecycleExecutor.java:569)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:539)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:387)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:284)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:180)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:328)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:138)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
    at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:60)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
    at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
    at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
    at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
Caused by: org.apache.maven.plugin.MojoExecutionException: Error reading assemblies: No assembly descriptors found.
    at org.apache.maven.plugin.assembly.mojos.AbstractAssemblyMojo.execute(AbstractAssemblyMojo.java:356)
    at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:490)
    at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:694)
    ... 17 more
Caused by: org.apache.maven.plugin.assembly.io.AssemblyReadException: No assembly descriptors found.
    at org.apache.maven.plugin.assembly.io.DefaultAssemblyReader.readAssemblies(DefaultAssemblyReader.java:206)
    at org.apache.maven.plugin.assembly.mojos.AbstractAssemblyMojo.execute(AbstractAssemblyMojo.java:352)
    ... 19 more

我没有看到我的错误。有人有解决方案吗？

Answer 1

这里有两个问题。首先，当使用您自己的描述符时，您必须指定路径您的自定义描述符文件（顺便说一下，您可以使用任何位置，但将描述符放在src/main/resources 中可能不是最佳选择，您真的不希望将描述符打包在您的应用程序中，我会使用标准位置，即src/main/assembly，如this page 中所述）。

<descriptors>
  <descriptor>src/main/assembly/jar-with-dependencies.xml</descriptor>
</descriptors>

其次，您的 configuration 元素当前位于 execution 块内，因此特定于 this 执行。换句话说，如果您在命令行上运行assembly:assembly，它将不适用。因此，如果您想使用自定义描述符调用 assembly:assembly，请使用：

mvn assembly:assembly -Ddescriptor=path/to/descriptor.xml

或者将configuration 移到execution 元素之外（使配置全局化）：

<project>
  ...
  <build>
    ...
    <plugins>
      <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <version>2.2-beta-5</version>
        <configuration>
          <descriptors>
            <descriptor>path/to/descriptor.xml</descriptor>
          </descriptors>
          ...
        </configuration>
      </plugin>
     </plugins>
     ...
   </build>
   ...
</project>

Answer 2

程序集试图在类路径中打开 /assemblies/${ref}.xml 检查这个

http://maven.apache.org/plugins/maven-assembly-plugin/xref/org/apache/maven/plugin/assembly/io/DefaultAssemblyReader.html