Maven exec插件主类丢失答案

【问题标题】：Maven exec plugin main class missingMaven exec插件主类丢失
【发布时间】：2011-08-10 10:22:42
【问题描述】：

我正在尝试通过 Hibernate 教程并在运行命令时遇到了困难

C:\Users\Eyal\workspace\FirstHibernateTutorial>mvn exec:java -Dexec.mainclass="o
rg.hsqldb.Server" -Dexec.args="-database.O file:target/data/tutorial" -e

并得到这些错误。

[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for
org.hibernate.tutorials:hibernate-tutorial:jar:1.0.0-SNAPSHOT
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artif
actId} instead.
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten t
he stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support buildin
g such malformed projects.
[WARNING]
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building First Hibernate Tutorial 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> exec-maven-plugin:1.2:java (default-cli) @ hibernate-tutorial >>>
[INFO]
[INFO] <<< exec-maven-plugin:1.2:java (default-cli) @ hibernate-tutorial <<<
[INFO]
[INFO] --- exec-maven-plugin:1.2:java (default-cli) @ hibernate-tutorial ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.964s
[INFO] Finished at: Thu Apr 21 18:31:10 IDT 2011
[INFO] Final Memory: 4M/15M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2:java (def
ault-cli) on project hibernate-tutorial: The parameters 'mainClass' for goal org
.codehaus.mojo:exec-maven-plugin:1.2:java are missing or invalid -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal o
rg.codehaus.mojo:exec-maven-plugin:1.2:java (default-cli) on project hibernate-t
utorial: The parameters 'mainClass' for goal org.codehaus.mojo:exec-maven-plugin
:1.2:java are missing or invalid
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:221)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:153)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:145)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProje
ct(LifecycleModuleBuilder.java:84)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProje
ct(LifecycleModuleBuilder.java:59)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBu
ild(LifecycleStarter.java:183)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(Lifecycl
eStarter.java:161)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Laun
cher.java:290)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.jav
a:230)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(La
uncher.java:409)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:
352)
Caused by: org.apache.maven.plugin.PluginParameterException: The parameters 'mai
nClass' for goal org.codehaus.mojo:exec-maven-plugin:1.2:java are missing or inv
alid
        at org.apache.maven.plugin.internal.DefaultMavenPluginManager.populatePl
uginFields(DefaultMavenPluginManager.java:576)
        at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getConfigu
redMojo(DefaultMavenPluginManager.java:529)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(Default
BuildPluginManager.java:92)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:209)
        ... 19 more
[ERROR]
[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 rea
d the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginParamete
rException

我确实更改了 pom 文件中的一件事。我添加了依赖项的版本。这是 pom.xml。我更改了它，因为没有它，我会收到有关缺少版本规范的错误。

    <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>org.hibernate.tutorials</groupId>
    <artifactId>hibernate-tutorial</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <name>First Hibernate Tutorial</name>

    <build>
        <!-- we dont want the version to be part of the generated war file name -->
        <finalName>${artifactId}</finalName>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>3.3.1.GA</version>
        </dependency>

        <!-- Because this is a web app, we also have a dependency on the servlet api. -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>[2.4,)</version>
        </dependency>

        <!-- Hibernate uses slf4j for logging, for our purposes here use the simple backend -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.5.6</version>
        </dependency>

        <!-- Hibernate gives you a choice of bytecode providers between cglib and javassist -->
        <dependency>
            <groupId>javassist</groupId>
            <artifactId>javassist</artifactId>
            <version>[3.0,)</version>
        </dependency>
    </dependencies>
</project>

我认为主要问题就在这条线上

The parameters 'mainClass' for goal org .codehaus.mojo:exec-maven-plugin:1.2:java are missing or invalid -> [Help 1]

为什么 mainClass 无效？你能看到我看不到的东西吗？

编辑：

好的，我将“mainclass”更改为“mainClass”，它给了我这个关于找不到“org.hsqldb.Server”的错误。我将 hsqldb.jar 添加到 Eclipse 的参考库中，但它仍然给我同样的错误。

这是堆栈打印：

C:\Users\Eyal\workspace\FirstHibernateTutorial>mvn exec:java -Dexec.mainClass="o
rg.hsqldb.Server" -Dexec.args="-database.O file:target/data/tutorial" -e
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for
org.hibernate.tutorials:hibernate-tutorial:jar:1.0.0-SNAPSHOT
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artif
actId} instead.
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten t
he stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support buildin
g such malformed projects.
[WARNING]
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building First Hibernate Tutorial 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> exec-maven-plugin:1.2:java (default-cli) @ hibernate-tutorial >>>
[INFO]
[INFO] <<< exec-maven-plugin:1.2:java (default-cli) @ hibernate-tutorial <<<
[INFO]
[INFO] --- exec-maven-plugin:1.2:java (default-cli) @ hibernate-tutorial ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.106s
[INFO] Finished at: Sat Apr 23 10:46:09 IDT 2011
[INFO] Final Memory: 4M/15M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2:java (def
ault-cli) on project hibernate-tutorial: An exception occured while executing th
e Java class. org.hsqldb.Server -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal o
rg.codehaus.mojo:exec-maven-plugin:1.2:java (default-cli) on project hibernate-t
utorial: An exception occured while executing the Java class. org.hsqldb.Server
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:217)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:153)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:145)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProje
ct(LifecycleModuleBuilder.java:84)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProje
ct(LifecycleModuleBuilder.java:59)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBu
ild(LifecycleStarter.java:183)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(Lifecycl
eStarter.java:161)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Laun
cher.java:290)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.jav
a:230)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(La
uncher.java:409)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:
352)
Caused by: org.apache.maven.plugin.MojoExecutionException: An exception occured
while executing the Java class. org.hsqldb.Server
        at org.codehaus.mojo.exec.ExecJavaMojo.execute(ExecJavaMojo.java:346)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(Default
BuildPluginManager.java:101)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor
.java:209)
        ... 19 more
Caused by: java.lang.ClassNotFoundException: org.hsqldb.Server
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:284)
        at java.lang.Thread.run(Thread.java:662)
[ERROR]
[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 rea
d the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionE
xception
C:\Users\Eyal\workspace\FirstHibernateTutorial>

【问题讨论】：

标签： java hibernate maven

【解决方案1】：

应该是mainClass 而不是mainclass。

-Dexec.mainClass="org.hsqldb.Server"

阅读更多关于 here 和 here 的信息。

并且 hsqldb 应该在您的 maven 依赖项中：

<dependency> 
  <groupId>org.hsqldb</groupId> 
  <artifactId>hsqldb</artifactId> 
  <version>2.0.0</version> 
</dependency>

【讨论】：

嗨，谢谢你的回答...你能告诉它为什么卡在“java.lang.ClassNotFoundException: org.hsqldb.Server”吗？
@Eyal - 在你的 pom.xml 中添加这个依赖。 <dependency> <groupId>org.hsqldb</groupId> <artifactId>hsqldb</artifactId> <version>2.0.0</version> </dependency>
缺少 'exec' 前缀，错误消息应该给出完整的参数名称，而不仅仅是：The parameters 'mainClass' for goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java are missing or invalid

【解决方案2】：

请注意，“配置”部分必须在执行部分之外（参见下面的示例）。否则你会得到“丢失或无效的 mainClass”错误。

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.2</version>
                <dependencies>
                    <dependency>
                        <groupId>org.versly</groupId>
                        <artifactId>versly-wsdoc</artifactId>
                        <version>1.0-SNAPSHOT</version>
                        <scope>compile</scope>
                    </dependency>
                </dependencies>
                <executions>
                    <execution>
                        <phase>prepare-package</phase>
                        <goals>
                            <goal>java</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <mainClass>org.versly.rest.wsdoc.RestDocAssembler</mainClass>
                    <arguments>
                        <argument>${project.build.directory}/classes</argument>
                    </arguments>
                </configuration>
            </plugin>

【讨论】：