即使没有 (public) Javadoc，如何强制使用 javadoc jar？
How to force a javadoc jar even though there is no (public) Javadoc?
我有一个 Maven 多模块项目，其中一些子模块仅供内部使用。我不想为它发布任何可见的 Javadoc，因为它不应该被第 3 方直接使用。其中没有一个 public 包（包名本身有类似 a.b.c.internal.d 的东西）。
但是，要将 jar 发布到 Maven Central，OSS Sonatype 要求所有库 jar 都有附带的源和 javadoc jar。
如何强制使用固定索引创建 javadoc jar 以告知子模块的用途？想到了一个package-info.java，但是我没有public个packages（所有带"internal"字样的package都被忽略了）。
我发现的一个非常丑陋的解决方法（我不会接受这个答案）是简单地触发一个错误并将出错时失败设置为假。然后 javadoc-plugin 处理一个空的 target/apidocs 文件夹并生成一个空的子模块-javadoc.jar.
我发现最容易触发错误的方法是在/src 根文件夹中创建一个空包-info.java。这会产生以下构建输出：
[INFO] --- maven-javadoc-plugin:3.1.1:jar (attach-javadocs) @
my-internal-module --- [INFO] 1 error [ERROR] MavenReportException:
Error while generating Javadoc: Exit code: 1 - javadoc: error - No
public or protected classes found to document.
Command line was: "C:\Program
Files\Java\jdk1.8.0_131\jre..\bin\javadoc.exe" @options @argfile
Refer to the generated Javadoc files in
'D:\workstation\my-parent-project\modules\my-internal-module\target\apidocs'
dir.
org.apache.maven.reporting.MavenReportException: Exit code: 1 -
javadoc: error - No public or protected classes found to document.
Command line was: "C:\Program
Files\Java\jdk1.8.0_131\jre..\bin\javadoc.exe" @options @argfile
Refer to the generated Javadoc files in
'D:\workstation\my-parent-project\modules\my-internal-module\target\apidocs'
dir.
at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.executeJavadocCommandLine(AbstractJavadocMojo.java:5763)
at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.executeReport(AbstractJavadocMojo.java:2152)
at org.apache.maven.plugins.javadoc.JavadocJar.doExecute(JavadocJar.java:189)
at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.execute(AbstractJavadocMojo.java:1911)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:154)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:146)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:309)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:194)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:107)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:993)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:345)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:191)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
[INFO] Building jar:
D:\workstation\my-parent-project\modules\my-internal-module\target\my-internal-module-6.0.0.beta-SNAPSHOT.2-javadoc.jar
使用以下插件配置：
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>3.1.1</version>
<executions>
<execution>
<id>attach-javadocs</id>
<goals>
<goal>jar</goal>
</goals>
<phase>package</phase>
<configuration>
<show>public</show>
<failOnError>false</failOnError>
<detectOfflineLinks>false</detectOfflineLinks>
<doclint>all,-missing</doclint>
<nohelp>true</nohelp>
<excludePackageNames>*.internal.*,testutil,demo</excludePackageNames>
<quiet>true</quiet>
</configuration>
</execution>
</executions>
<configuration>
<failOnError>false</failOnError>
</configuration>
</plugin>
虽然这满足了我的主要需求（以一种非常丑陋的方式），但我更喜欢带有一个主要自定义条目的 javadoc，我在其中解释了模块的用途。
不要使用 Javadoc 工具生成包含非标准内容的 jar：请使用 maven-jar-plugin 手动创建一个。
初始解取自https://vzurczak.wordpress.com/2014/08/01/generate-an-empty-javadoc-jar-file/
这是我确定的最终解决方案，当在父 pom 中配置时，它通常适用于所有子模块：
定义两个配置文件：
- 如果子模块中没有自定义 javadoc 文件夹（缺少 src/main/javadoc），则执行标准 javadoc 插件
- 如果子模块中存在自定义 javadoc 文件夹（src/main/javadoc 存在），则通过 jar 插件执行自定义 javadoc
Maven 配置：
<profiles>
<profile>
<id>standard-javadoc</id>
<activation>
<file><missing>src/main/javadoc</missing></file>
</activation>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<executions>
<execution>
<id>attach-javadocs</id>
<goals>
<goal>jar</goal>
</goals>
<phase>package</phase>
<configuration>
<show>public</show>
<failOnError>false</failOnError>
<detectOfflineLinks>false</detectOfflineLinks>
<doclint>all,-missing</doclint>
<nohelp>true</nohelp>
<excludePackageNames>*.internal.*,testutil,demo</excludePackageNames>
<quiet>true</quiet>
</configuration>
</execution>
</executions>
<configuration>
<failOnError>false</failOnError>
</configuration>
</plugin>
</plugins>
</build>
</profile>
<profile>
<id>custom-javadoc</id>
<activation>
<file><exists>src/main/javadoc</exists></file>
</activation>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>jar</goal>
</goals>
<configuration>
<classifier>javadoc</classifier>
<classesDirectory>${project.basedir}/src/main/javadoc</classesDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>
我有一个 Maven 多模块项目，其中一些子模块仅供内部使用。我不想为它发布任何可见的 Javadoc，因为它不应该被第 3 方直接使用。其中没有一个 public 包（包名本身有类似 a.b.c.internal.d 的东西）。
但是，要将 jar 发布到 Maven Central，OSS Sonatype 要求所有库 jar 都有附带的源和 javadoc jar。
如何强制使用固定索引创建 javadoc jar 以告知子模块的用途？想到了一个package-info.java，但是我没有public个packages（所有带"internal"字样的package都被忽略了）。
我发现的一个非常丑陋的解决方法（我不会接受这个答案）是简单地触发一个错误并将出错时失败设置为假。然后 javadoc-plugin 处理一个空的 target/apidocs 文件夹并生成一个空的子模块-javadoc.jar.
我发现最容易触发错误的方法是在/src 根文件夹中创建一个空包-info.java。这会产生以下构建输出：
[INFO] --- maven-javadoc-plugin:3.1.1:jar (attach-javadocs) @ my-internal-module --- [INFO] 1 error [ERROR] MavenReportException: Error while generating Javadoc: Exit code: 1 - javadoc: error - No public or protected classes found to document.
Command line was: "C:\Program Files\Java\jdk1.8.0_131\jre..\bin\javadoc.exe" @options @argfile
Refer to the generated Javadoc files in 'D:\workstation\my-parent-project\modules\my-internal-module\target\apidocs' dir.
org.apache.maven.reporting.MavenReportException: Exit code: 1 - javadoc: error - No public or protected classes found to document.
Command line was: "C:\Program Files\Java\jdk1.8.0_131\jre..\bin\javadoc.exe" @options @argfile
Refer to the generated Javadoc files in 'D:\workstation\my-parent-project\modules\my-internal-module\target\apidocs' dir.
at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.executeJavadocCommandLine(AbstractJavadocMojo.java:5763) at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.executeReport(AbstractJavadocMojo.java:2152) at org.apache.maven.plugins.javadoc.JavadocJar.doExecute(JavadocJar.java:189) at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.execute(AbstractJavadocMojo.java:1911) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:154) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:146) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81) at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:309) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:194) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:107) at org.apache.maven.cli.MavenCli.execute(MavenCli.java:993) at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:345) at org.apache.maven.cli.MavenCli.main(MavenCli.java:191) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289) at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)[INFO] Building jar: D:\workstation\my-parent-project\modules\my-internal-module\target\my-internal-module-6.0.0.beta-SNAPSHOT.2-javadoc.jar
使用以下插件配置：
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>3.1.1</version>
<executions>
<execution>
<id>attach-javadocs</id>
<goals>
<goal>jar</goal>
</goals>
<phase>package</phase>
<configuration>
<show>public</show>
<failOnError>false</failOnError>
<detectOfflineLinks>false</detectOfflineLinks>
<doclint>all,-missing</doclint>
<nohelp>true</nohelp>
<excludePackageNames>*.internal.*,testutil,demo</excludePackageNames>
<quiet>true</quiet>
</configuration>
</execution>
</executions>
<configuration>
<failOnError>false</failOnError>
</configuration>
</plugin>
虽然这满足了我的主要需求（以一种非常丑陋的方式），但我更喜欢带有一个主要自定义条目的 javadoc，我在其中解释了模块的用途。
不要使用 Javadoc 工具生成包含非标准内容的 jar：请使用 maven-jar-plugin 手动创建一个。
初始解取自https://vzurczak.wordpress.com/2014/08/01/generate-an-empty-javadoc-jar-file/
这是我确定的最终解决方案，当在父 pom 中配置时，它通常适用于所有子模块：
定义两个配置文件：
- 如果子模块中没有自定义 javadoc 文件夹（缺少 src/main/javadoc），则执行标准 javadoc 插件
- 如果子模块中存在自定义 javadoc 文件夹（src/main/javadoc 存在），则通过 jar 插件执行自定义 javadoc
Maven 配置：
<profiles>
<profile>
<id>standard-javadoc</id>
<activation>
<file><missing>src/main/javadoc</missing></file>
</activation>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<executions>
<execution>
<id>attach-javadocs</id>
<goals>
<goal>jar</goal>
</goals>
<phase>package</phase>
<configuration>
<show>public</show>
<failOnError>false</failOnError>
<detectOfflineLinks>false</detectOfflineLinks>
<doclint>all,-missing</doclint>
<nohelp>true</nohelp>
<excludePackageNames>*.internal.*,testutil,demo</excludePackageNames>
<quiet>true</quiet>
</configuration>
</execution>
</executions>
<configuration>
<failOnError>false</failOnError>
</configuration>
</plugin>
</plugins>
</build>
</profile>
<profile>
<id>custom-javadoc</id>
<activation>
<file><exists>src/main/javadoc</exists></file>
</activation>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>jar</goal>
</goals>
<configuration>
<classifier>javadoc</classifier>
<classesDirectory>${project.basedir}/src/main/javadoc</classesDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
</profiles>