72

我正在遵循创建 maven 插件的教程，并且无法运行 mvn install 而不会出现错误。当注释应该为我生成它们时，该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。这是我的主要课程：

@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());
        }
    }
}

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>

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
4

6 回答 6

65

也许这与 Maven 中未解决的问题有关：https ://issues.apache.org/jira/browse/MNG-5346

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>

但请参阅 JIRA 问题中的评论以获得更详细的解决方案！

于 2013-09-25T08:15:33.970 回答
40

在阅读了Gyro 发布的 Jira 问题后，我在我的 pom 中添加了以下几行，一切都编译得很好。

<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>
于 2013-09-25T08:34:00.803 回答
37

如上一个答案所述，这是一个错误，现在已修复。

您只需要告诉 maven 它应该使用更新版本的maven-plugin-plugin.

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>
于 2015-06-25T06:39:20.890 回答
16

简单地将 maven 插件版本增加到 3.3 或 3.4 不会解决任何问题（正如一些人所说）。

您必须default-descriptor在正确的阶段添加最少的执行。所以构建信息的最小配置如下：

<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>

与maven-plugin-plugin版本无关。（可以是 3.1, 3.2, 3.3. 3.4 （没有测试其他的））。

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] ------------------------------------------------------------------------

如果您不想在 pom 中包含构建标签，则另一种选择是，您可以在 Mojo 上使用 javadocs。例如：

/**
 * @goal run123
 */
@Mojo(name = "run123")
public class MyMojo extends AbstractMojo {
}

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] ------------------------------------------------------------------------

请参阅本指南以获取更多信息 http://maven.apache.org/plugin-tools/maven-plugin-plugin/examples/using-annotations.html

于 2016-03-20T00:21:05.570 回答
5

上面的答案很好——我想通过添加资源来查找最新版本来扩充它们： https ://mvnrepository.com/artifact/org.apache.maven.plugins/maven-plugin-plugin

2019 年 4 月 2 日——我遇到了同样的错误，并使用 3.6.0 解决了它

于 2019-04-02T19:52:58.300 回答
1

最初我认为 Gyro 的回答解决了这个错误。但后来在执行目标时失败了。

mvn sample.plugin:hello-maven-plugin:1.0-SNAPSHOT:sayhi

生产

[错误] 在插件示例中找不到目标“sayhi”。插件：hello-maven-plugin:1.0-SNAPSHOT 在可用目标中-> [帮助 1]

结果是

skipErrorNoDescriptorsFound

只压制了错误。即它没有解决根本问题。我删除了此修复程序。

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

它需要在

.../Development/my-maven-plugin/src/main/Java/sample/plugin/GreetingMojo.java

于 2017-07-10T13:01:00.907 回答