未能执行目标 org.apache.maven.plugins:maven-compiler-plugin:3.1:compile

Question

鉴于以下 pom.xml：

<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>com.myApp</groupId>
    <artifactId>malloc</artifactId>
    <version>0.0.1</version>
    <packaging>war</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    </properties>

    <repositories>
        <repository>
            <id>project</id>
            <url>file:///${basedir}/lib</url>
        </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>com.myApp</groupId>
            <artifactId>myApp.core</artifactId>
            <version>1.0.0</version>
        </dependency>
        ... //other dependencies
    </dependencies>
    <build>
        <sourceDirectory>src</sourceDirectory>
        <resources>
            <resource>
                <directory>src</directory>
                <excludes>
                    <exclude>**/*.java</exclude>
                </excludes>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <archive>
                        <manifest>
                        <addClasspath>true</addClasspath>
                         </manifest>
                         <addMavenDescriptor>false</addMavenDescriptor>
                    </archive>
                    <webResources>
                         <webResource> 
                           <directory>${project.build.directory}/WebContent/WEB-INF</directory> 
                           <includes> 
                             <include>web.xml</include> 
                           </includes> 
                           <targetPath>WEB-INF</targetPath> 
                           <filtering>true</filtering> 
                         </webResource>
                    </webResources>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.10</version>
                <executions>
                    <execution>
                    <id>copy-dependencies</id>
                    <phase>package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                            <outputDirectory>${project.build.directory}/WebContent/WEB-INF/lib</outputDirectory>
                            <includeScope>runtime</includeScope>
                            <overWriteReleases>false</overWriteReleases>
                            <overWriteSnapshots>false</overWriteSnapshots>
                            <overWriteIfNewer>true</overWriteIfNewer>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

以及以下项目结构：

我希望 maven-dependency-plugin 会将所有依赖项复制到 WebContent/WEB-INF/lib 但是当我运行时

mvn clean install

产生以下错误：

[INFO] Scanning for projects...
[INFO] 
[INFO] Using the builder org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder with a thread count of 1
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building api-malloc 0.0.1
[INFO] ------------------------------------------------------------------------
[WARNING] The POM for com.oracle:ojdbc6:jar:10.2.0.4.0 is missing, no dependency information available
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ api-malloc ---
[INFO] Deleting C:\Development\malloc\target
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ api-malloc ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ api-malloc ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 8 source files to C:\Development\malloc\target\classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] /C:/Development/malloc/src/com/myApp/api/malloc/dto/RegionTypeDTO.java:[3,34] package com.myApp.api.core.dto does not exist
[ERROR] /C:/Development/malloc/src/com/myApp/api/malloc/dto/RegionTypeDTO.java:[5,39] cannot find symbol
  symbol: class IDTO
[INFO] 26 errors 
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.209 s
[INFO] Finished at: 2015-11-26T15:33:40-05:00
[INFO] Final Memory: 21M/227M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project malloc: Compilation failure: Compilation failure:
[ERROR] /C:/Development/malloc/src/com/myApp/api/malloc/dto/RegionTypeDTO.java:[3,34] package com.myApp.api.core.dto does not exist
[ERROR] /C:/Development/malloc/src/com/myApp/api/malloc/dto/RegionTypeDTO.java:[5,39] cannot find symbol
[ERROR] symbol: class IDTO

[ERROR] location: class com.myApp.api.malloc.controllers.TestController
[ERROR] -> [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/MojoFailureException

我注意到 WEB-INF/lib 文件夹总是空的，没有复制 maven 依赖项。

我怀疑 copy-dependencies 插件在编译阶段之前没有运行，但我真的不知道 - 我错过了什么？

Answer 1

如果编译失败，copy-dependencies 目标确实永远不会执行，因为它的绑定是在 compile 阶段之后的package 阶段（默认情况下，Maven 编译器插件链接到该阶段）。

如果希望它在compile 阶段之前运行，则需要更改copy-dependencies 目标执行的阶段值。更改为 process-resources 应该没问题，也应该有意义。

<phase>package</phase>

有关阶段的完整描述，您可以查看官方文档，here。

您还应该修复构建输出指向的编译错误。我看到 sourceDirectory 元素覆盖了 Maven 默认使用的 Java 源代码 (src\main\java)，因此我想您的代码直接位于 src 文件夹下。

更新：the package X does not exist 错误发生在代码引用 Java 编译器未解析的包时，因此它无法在类路径中看到该包，这意味着在声明的依赖项：myApp.core 是否包含该包和类？如果是，那么 repositories 元素（lib 文件夹）可能没有正确提供 myApp 依赖项。

您可以尝试使用指定here 的Maven 安装插件在.m2 maven 缓存中本地安装依赖项。 您可以从命令行执行如下：

mvn org.apache.maven.plugins:maven-install-plugin:2.5.2:install-file  
       -Dfile=lib\myApp.core-1.0.0.jar \
       -DgroupId=com.myApp \
       -DartifactId=myApp.core \
       -Dversion=1.0.0 \
       -Dpackaging=jar \

---

旁注：Maven 更喜欢小写的 groupid 和 artifactid 标记。此外，Maven 约定也使用破折号来分隔标记（即myapp-core），而不是使用驼峰式大小写（即myApp）。