在插件 org.codehaus.mojo 中找不到目标“devmode”

Question

我是 GWT 和 Maven 的初学者。我在 Eclipse 中创建了一个新的 GWT 应用程序项目。然后，我通过右键单击项目名称 => Configure => Convert to Maven Project 将该项目转换为 Maven 项目，我看到为此生成了一个 pom 文件项目。接下来，我作为 Maven 构建的项目运行，但它没有被编译，因为那里没有指定目标。实际上，我不明白在那个目标部分到底要写什么，因此，我在下面写了 package，然后我再次构建了 maven，它编译成功了。

之后，我尝试使用 设置新项目 部分下Run the GWT Project 中提到的第二步，在 SuperDevMode 的命令提示符中运行这个 maven 项目。但是，在命令提示符上执行这些步骤时，我收到了一个错误，即找不到 devmode。这是我的命令提示符日志：

C:\Users\TEST>cd eclipse-workspace/MyWebApp

C:\Users\TEST\eclipse-workspace\MyWebApp>mvn war:exploded
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building MavenApp 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-war-plugin:3.1.0:exploded (default-cli) @ abcdef ---
[INFO] Exploding webapp
[INFO] Assembling webapp [abcdef] in [C:\Users\TEST\eclipse-workspace\MyWebApp\target\abcdef-0.0.1-SNAPSHOT]
[INFO] Processing war project
[INFO] Webapp assembled in [63 msecs]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.920 s
[INFO] Finished at: 2017-08-30T11:24:53+05:30
[INFO] Final Memory: 12M/107M
[INFO] ------------------------------------------------------------------------

C:\Users\TEST\eclipse-workspace\MyWebApp>mvn gwt:devmode
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.301 s
[INFO] Finished at: 2017-08-30T11:25:02+05:30
[INFO] Final Memory: 8M/107M
[INFO] ------------------------------------------------------------------------
[ERROR] Could not find goal 'devmode' in plugin org.codehaus.mojo:gwt-maven-plugin:2.8.1 among available goals clean, compile, compile-report, css, debug, eclipse, eclipseTest, generateAsync, help, i18n, mergewebxml, resources, run, run-codeserver, source-jar, test -> [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/MojoNotFoundException

这是我的 pom.xml 文件：

<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>MyWebApp</groupId>
  <artifactId>abcdef</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <build>
    <sourceDirectory>src</sourceDirectory>
    <testSourceDirectory>test</testSourceDirectory>
    <resources>
      <resource>
        <directory>src</directory>
        <excludes>
          <exclude>**/*.java</exclude>
        </excludes>
      </resource>
    </resources>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.6.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <name>MavenApp</name>
  <description>It is a maven app</description>
</project>

我进行了很多搜索以解决此错误，但没有找到该问题的解决方案。请帮助我解决此问题，因为我对如何解决它感到非常困惑。

编辑：经过进一步研究，我使用mvn gwt:run 作为命令mvn gwt:devmode 的替代，但在命令提示符下仍然出现另一个错误，如下所示：

[ERROR] Failed to execute goal org.codehaus.mojo:gwt-maven-plugin:2.8.1:run (default-cli) on project MyWebApp: The parameters 'runTarget' for goal org.codehaus.mojo:gwt-maven-plugin:2.8.1:run are missing or invalid

Answer 1

如果没有比gwt:devmode 更多的信息，Maven 将尝试根据其默认设置找到合适的插件。碰巧有一个 gwt-maven-plugin 以 org.codehaus.mojo 作为 groupId，适合 Maven 内置插件解析。

但这不是你要找的插件。

您可能正在尝试使用this one，因此只需将其添加到您的pom.xml 中的<plugins> 部分：

<plugin>
  <groupId>net.ltgt.gwt.maven</groupId>
  <artifactId>gwt-maven-plugin</artifactId>
  <version>1.0-rc-8</version>
  <extensions>true</extensions>
  <configuration>
    <moduleName>com.example.app.App</moduleName>
  </configuration>
</plugin>

根据需要调整 moduleName。

Answer 2

好吧，我能够通过将一些依赖项、插件和配置从 pom.xml 文件（在 webAppCreator 使用 maven 创建的项目中生成）复制到我项目的 pom.xml 文件中来解决这个问题在 Eclipse 中创建。所以，这是我最终创建的 pom.xml 文件：

<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>MyPersonalProject</groupId>
  <artifactId>MyPersonalProject</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>

    <!-- Setting maven.compiler.source to something different to 1.8
         needs that you configure the sourceLevel in gwt-maven-plugin since
         GWT compiler 2.8 requires 1.8 (see gwt-maven-plugin block below) -->
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>

    <!-- Don't let your Mac use a crazy non-standard encoding -->
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  </properties>
  <dependencyManagement>
    <dependencies>
      <!-- ensure all GWT deps use the same version (unless overridden) -->
      <dependency>
        <groupId>com.google.gwt</groupId>
        <artifactId>gwt</artifactId>
        <version>2.8.1</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <dependencies>
    <dependency>
      <groupId>com.google.gwt</groupId>
      <artifactId>gwt-servlet</artifactId>
      <scope>runtime</scope>
    </dependency>
    <dependency>
      <groupId>com.google.gwt</groupId>
      <artifactId>gwt-user</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>com.google.gwt</groupId>
      <artifactId>gwt-dev</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
  <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
    <sourceDirectory>src</sourceDirectory>
    <testSourceDirectory>test</testSourceDirectory>
    <resources>
      <resource>
        <directory>src</directory>
        <excludes>
          <exclude>**/*.java</exclude>
        </excludes>
      </resource>
    </resources>
    <plugins>
    <plugin>
        <groupId>net.ltgt.gwt.maven</groupId>
        <artifactId>gwt-maven-plugin</artifactId>
        <version>1.0-rc-6</version>
        <executions>
          <execution>
            <goals>
              <goal>import-sources</goal>
              <goal>compile</goal>
              <goal>import-test-sources</goal>
              <goal>test</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <moduleName>mypackage.MyPersonalproject</moduleName>
          <failOnError>true</failOnError>
          <!-- GWT compiler 2.8 requires 1.8, hence define sourceLevel here if you use
               a different source language for java compilation -->
          <sourceLevel>1.8</sourceLevel>
          <!-- Compiler configuration -->
          <compilerArgs>
            <!-- Ask GWT to create the Story of Your Compile (SOYC) (gwt:compile) -->
            <arg>-compileReport</arg>
            <arg>-XcompilerMetrics</arg>
          </compilerArgs>
          <!-- DevMode configuration -->
          <warDir>${project.build.directory}/${project.build.finalName}</warDir>
          <classpathScope>compile+runtime</classpathScope>
          <!-- URL(s) that should be opened by DevMode (gwt:devmode). -->
          <startupUrls>
            <startupUrl>MyPersonalProject.html</startupUrl>
          </startupUrls>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.6.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

当我在命令提示符中使用 maven 运行此应用程序时，它运行成功，除了在命令提示符日志中显示 2 或 3 个警告。另外，我注意到版本中生成的 SNAPSHOT 与 Eclipse 创建的 pom.xml 与命令提示符下的 maven 项目创建的相比是不同的。