使用Lambdas时，Maven插件构建失败 [英] Maven Plugin Build fails when Lambdas are used

问题描述

我写了一个maven插件/ mojo来生成一些代码。该插件运行良好，并使用Java JDK 1.8构建。

I wrote a maven plugin/mojo to generate some code. The plugin works well, and is built in Java JDK 1.8.

我看到了一些奇怪的行为：它构建，安装等等，如果我使用pre -1.8语法，但是一旦我使用Java 8 Lambda表达式，执行 mvn clean install 时会出现以下错误：

I am seeing an odd bit of behavior though: It builds, installs, etc just fine if I use pre-1.8 syntax, but as soon as I use a Java 8 Lambda expression, I get the following error when executing mvn clean install:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-plugin-plugin:3.2:descriptor (default-descriptor) on project my-maven-plugin: Execution default-descriptor of goal org.apache.maven.plugins:maven-plugin-plugin:3.2:descriptor failed: 13557 -> [Help 1]

这是我的pom：

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.my.group.id</groupId>
    <artifactId>my-maven-plugin</artifactId>
    <packaging>maven-plugin</packaging>
    <version>1.0-SNAPSHOT</version>

    <name>My Maven Mojo</name>
    <url>http://maven.apache.org</url>

    <properties>
        <org.springframework.version>4.0.1.RELEASE</org.springframework.version>
        <joda-time.version>2.3</joda-time.version>
    </properties>

    <dependencies>
       <!-- several dependencies -->
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.2</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <!-- The following manual call to the maven-plugin plugin is necessary to get around a bug in maven 3.1.1.
             If the build server gets updated to 3.2.2+ we can remove this -->
            <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>

    <distributionManagement>
        <repository>
            <id>inin-release</id>
            <name>ININ Release Repository</name>
            <url>http://nexus.infrastructure.inintca.com/nexus/content/repositories/inin-release</url>
        </repository>
        <snapshotRepository>
            <id>inin-snapshot</id>
            <name>ININ Snapshot Repository</name>
            <url>http://nexus.infrastructure.inintca.com/nexus/content/repositories/inin-snapshot</url>
        </snapshotRepository>
    </distributionManagement>
</project>

当我尝试使用lambda定义 FileFilter 而不是传统的匿名内部类。

The issue appears in this case when I attempt to use a lambda to define a FileFilter rather than the traditional anonymous inner class.

这有效：

List<File> controllerFiles = Arrays.asList(packageDirFile.listFiles(new FileFilter()
{
    @Override
    public boolean accept(File file)
    {
        return file.isFile() && file.getName().endsWith(".java");
    }
}));

虽然这会产生上述错误：

While this produces the aforementioned error:

List<File>
        controllerFiles =
        Arrays.asList(packageDirFile.listFiles(file -> file.isFile() &&
                file.getName().endsWith(".java")));

显然，鉴于我有一个解决方法，这并不重要，但lambda比匿名内部类IMO，鉴于我在Java 8中工作，我更喜欢使用它。任何人都有任何提示，特别是考虑到我已经将skipErrorNoDescriptorsFound设置为true？

Obviously given that I have a workaround this isn't critical, but the lambda is much cleaner than the anonymous inner class IMO and given that I'm working in Java 8 I'd much prefer to use it. Anybody have any tips, particularly given that I've already set skipErrorNoDescriptorsFound to true?

推荐答案

MPLUGIN-273 说如果构建使用 maven-plugin-plugin ，lambda就可以工作版本 3.3 。显示的错误消息引用了 maven-plugin-plugin 版本 3.2 。确保您使用的是正确版本的插件，看看是否能解决问题。

The note on MPLUGIN-273 says lambdas work if the build is using maven-plugin-plugin version 3.3. The error message shown references maven-plugin-plugin version 3.2 . Make sure you're using the correct version of the plugin and see if that fixes the issue.

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