Java 基本的 maven 插件项目不工作，Mojo 插件描述符不生成
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Basic maven plugin project not working, Mojo plugin descriptors not generating
提问by coderatchet
I am following the tutorialfor creating a maven plugin and cannot run mvn install without getting errors. The info complains that i don't have the required mojo descriptors when the annotations should be generating them for me. I am running maven 3.0.5 and using intellij as my ide. here is my Main class:
我正在遵循创建 maven 插件的教程，并且无法运行 mvn install 而不会出错。当注释应该为我生成它们时，信息抱怨我没有所需的 mojo 描述符。我正在运行 maven 3.0.5 并使用 intellij 作为我的 ide。这是我的主课：
@Mojo(name = "modify-connector")
public class ComplianceMojo extends AbstractMojo {
@Parameter
private String artifactId;
@Parameter
private String version;
@Override
public void execute() throws MojoExecutionException, MojoFailureException {
File jar = new File(getPluginContext().get("project.build.directory") + "/"
+ getPluginContext().get("project.build.finalname") + "/" + artifactId + "-" + version);
if(jar.exists()){
getLog().info("The file exists! " + jar.getAbsolutePath());
} else {
getLog().info("The file does not exist: " + jar.getAbsolutePath());
}
}
}
And here is my pom.xml
这是我的 pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>mysql-jdbc-compliance-maven-plugin</groupId>
<artifactId>mysql-jdbc-compliance-maven-plugin</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>maven-plugin</packaging>
<dependencies>
<dependency>
<groupId>org.apache.maven</groupId>
<artifactId>maven-plugin-api</artifactId>
<version>2.0</version>
</dependency>
<dependency>
<groupId>org.apache.maven.plugin-tools</groupId>
<artifactId>maven-plugin-annotations</artifactId>
<version>3.2</version>
<scope>provided</scope>
</dependency>
</dependencies>
</project>
Note:I had to separately add the annotations dependency as the main plugin api did not contain these classes. when i run mvn install on my project, the output is as follows:
注意：我必须单独添加注释依赖项，因为主插件 api 不包含这些类。当我在我的项目上运行 mvn install 时，输出如下：
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.867s
[INFO] Finished at: Wed Sep 25 17:45:55 EST 2013
[INFO] Final Memory: 8M/244M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-plugin-plugin:2.9:descriptor (default-descriptor) on project mysql-jdbc-compliance-maven-plugin: Error extracting plugin descriptor: 'No mojo definitions were found for plugin: mysql-jdbc-compliance-maven-plugin:mysql-jdbc-compliance-maven-plugin.' -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
采纳答案by coderatchet
after reading the Jira Issue that Gyro posted, i added the following lines to my pom and everything compiled nicely.
阅读Gyro 发布的Jira 问题后，我将以下几行添加到我的 pom 中，并且所有内容都编译得很好。
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<version>3.2</version>
<configuration>
<goalPrefix>mysql-jdbc-compliance</goalPrefix>
</configuration>
<executions>
<execution>
<id>default-descriptor</id>
<goals>
<goal>descriptor</goal>
</goals>
<phase>process-classes</phase>
</execution>
<execution>
<id>help-descriptor</id>
<goals>
<goal>helpmojo</goal>
</goals>
<phase>process-classes</phase>
</execution>
</executions>
</plugin>
</plugins>
</build>
回答by Gyro Gearless
Maybe this is related to a unresolved issue in Maven: https://issues.apache.org/jira/browse/MNG-5346
也许这与 Maven 中未解决的问题有关：https: //issues.apache.org/jira/browse/MNG-5346
For my plugin projects, i could workaround by adding an explicit execution of the maven-plugin-plugin:
对于我的插件项目，我可以通过添加 maven-plugin-plugin 的显式执行来解决：
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<version>3.2</version>
<configuration>
<!-- see http://jira.codehaus.org/browse/MNG-5346 -->
<skipErrorNoDescriptorsFound>true</skipErrorNoDescriptorsFound>
</configuration>
<executions>
<execution>
<id>mojo-descriptor</id>
<goals>
<goal>descriptor</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
But see the comments in the JIRA issue for more elaborate solutions!
但请参阅 JIRA 问题中的评论以获得更详细的解决方案！
回答by Jmini
As mentioned in the previous answer, this was a bug and it is now fixed.
正如之前的回答中提到的，这是一个错误，现在已修复。
You just need to tell maven it should use a newer version of the maven-plugin-plugin.
您只需要告诉 Maven 它应该使用更新版本的maven-plugin-plugin.
Here is how my pom file looks like:
这是我的 pom 文件的样子：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<!-- ...other maven config... -->
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<version>3.3</version>
</plugin>
</plugins>
</build>
</project>
回答by randomUser56789
Simply incrementing maven plugin version to 3.3 or 3.4
只需将 Maven 插件版本增加到 3.3 或 3.4
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<version>3.3</version>
</plugin>
</plugins>
</build>
won't fix any issue (as some has stated).
不会解决任何问题（正如某些人所说）。
You have to add a minimum of default-descriptorexecution with the correct phase.
So the minimum config of build information is as follows:
您必须default-descriptor在正确的阶段添加最少的执行。所以构建信息的最低配置如下：
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<version>3.1</version>
<executions>
<execution>
<id>default-descriptor</id>
<phase>process-classes</phase>
</execution>
</executions>
</plugin>
</plugins>
</build>
irrespective of maven-plugin-pluginversion. (it can be 3.1, 3.2, 3.3. 3.4 (didn't test the others)).
与maven-plugin-plugin版本无关。（它可以是 3.1, 3.2, 3.3. 3.4 （没有测试其他））。
will yield:
将产生：
...
[INFO] --- maven-plugin-plugin:3.2:descriptor (default-descriptor) @ example-maven-plugin ---
[WARNING] Using platform encoding (UTF-8 actually) to read mojo metadata, i.e. build is platform dependent!
[INFO] Applying mojo extractor for language: java-annotations
[INFO] Mojo extractor for language: java-annotations found 1 mojo descriptors.
[INFO] Applying mojo extractor for language: java
[INFO] Mojo extractor for language: java found 0 mojo descriptors.
[INFO] Applying mojo extractor for language: bsh
[INFO] Mojo extractor for language: bsh found 0 mojo descriptors.
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
Another option if you don't want to have build tags in your pom, you can use javadocs on your Mojo. For instance:
如果你不想在你的 pom 中有构建标签，你可以在你的 Mojo 上使用 javadocs。例如：
/**
* @goal run123
*/
@Mojo(name = "run123")
public class MyMojo extends AbstractMojo {
}
will yield:
将产生：
...
[INFO] --- maven-plugin-plugin:3.2:descriptor (default-descriptor) @ example-maven-plugin ---
[WARNING] Using platform encoding (UTF-8 actually) to read mojo metadata, i.e. build is platform dependent!
[INFO] Applying mojo extractor for language: java-annotations
[INFO] Mojo extractor for language: java-annotations found 0 mojo descriptors.
[INFO] Applying mojo extractor for language: java
[INFO] Mojo extractor for language: java found 1 mojo descriptors.
[INFO] Applying mojo extractor for language: bsh
[INFO] Mojo extractor for language: bsh found 0 mojo descriptors.
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
Please refer to this guide for more info http://maven.apache.org/plugin-tools/maven-plugin-plugin/examples/using-annotations.html
有关更多信息，请参阅本指南 http://maven.apache.org/plugin-tools/maven-plugin-plugin/examples/using-annotations.html
回答by Shane Gannon
Initially I thought Gyro's answer fixed the error. But later when executing the goal it failed.
最初我认为 Gyro 的回答修复了错误。但是后来在执行目标时失败了。
mvn sample.plugin:hello-maven-plugin:1.0-SNAPSHOT:sayhi
mvn sample.plugin:hello-maven-plugin:1.0-SNAPSHOT:sayhi
produced
产生
[ERROR] Could not find goal 'sayhi' in plugin sample.plugin:hello-maven-plugin:1.0-SNAPSHOT among available goals -> [Help 1]
[错误] 在可用目标中的插件 sample.plugin:hello-maven-plugin:1.0-SNAPSHOT 中找不到目标 'sayhi' -> [帮助 1]
Turns out that
原来如此
skipErrorNoDescriptorsFound
跳过错误NoDescriptorsFound
only suppressed the error. i.e. It did not resolve the underlying problem. I removed this fix.
只能抑制错误。即它没有解决根本问题。我删除了此修复程序。
After that the solution was simple (and the cause purely my fault). When I created GreetingMojo.java I placed it in the following directory
在那之后，解决方案很简单（原因纯粹是我的错）。当我创建 GreetingMojo.java 时，我将它放在以下目录中
.../Development/my-maven-plugin/src/sample/plugin/GreetingMojo.java
.../Development/my-maven-plugin/src/sample/plugin/GreetingMojo.java
It needed to be under
它需要在
.../Development/my-maven-plugin/src/main/Java/sample/plugin/GreetingMojo.java
.../Development/my-maven-plugin/src/main/Java/sample/plugin/GreetingMojo.java
回答by solbs
Great answers above -- I'd like to augment them by adding a resource to find the latest version: https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-plugin-plugin
上面的好答案 - 我想通过添加资源来查找最新版本来增加它们：https: //mvnrepository.com/artifact/org.apache.maven.plugins/maven-plugin-plugin
April 2, 2019 -- I encountered the same error above and resolved it by using 3.6.0
2019 年 4 月 2 日 -- 我遇到了上述相同的错误并通过使用 3.6.0 解决了它
