java - Maven插件执行失败

Question

Maven 配置失败，这条线毁了我星期五的晚上，但我仍然无法解决它。嗯，我是 Visual Studio Code 的忠实粉丝，所以我决定将 vscode 切换到 Eclipse 进行 Java 开发。但这不是问题，当我尝试添加外部 java 库时就会出现问题。我无法使用它，并且我只是收到类似 Class-not-Found 之类的错误。

嗯，这是我在 vscode 中的项目结构

   [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project in.blackpaper.topdf: Compilation failure

这是我在安装 mvn 插件时收到的错误消息。

 mvn clean install

[DEBUG] incrementalBuildHelper#beforeRebuildExecution
[INFO] Compiling 1 source file to E:\Documents\Java\in.blackpaper.topdf\target\classes
[DEBUG] incrementalBuildHelper#afterRebuildExecution
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.086 s
[INFO] Finished at: 2018-04-17T11:23:29+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project in.blackpaper.topdf: Compilation failure
[ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?
[ERROR]
[ERROR] -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project in.blackpaper.topdf: Compilation failure
No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:213)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:290)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:194)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (Unknown Source)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (Unknown Source)
    at java.lang.reflect.Method.invoke (Unknown Source)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)
Caused by: org.apache.maven.plugin.compiler.CompilationFailureException: Compilation failure
No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

    at org.apache.maven.plugin.compiler.AbstractCompilerMojo.execute (AbstractCompilerMojo.java:1161)
    at org.apache.maven.plugin.compiler.CompilerMojo.execute (CompilerMojo.java:168)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:208)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:290)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:194)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (Unknown Source)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (Unknown Source)
    at java.lang.reflect.Method.invoke (Unknown Source)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)
[ERROR]
[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

嗯，我也尝试与 vscode 开发人员解决我的问题，但仍然无法解决。这是我在vscode-github中提出的问题

vscode-java/issue#509

嗯，我的问题与之前提出的所有有关 maven-plugins 的问题不同，我尝试了所有可用的解决方案，但无法明白要点。

提前致谢。

Answer 1

您使用的 Java 安装不是 Java 开发工具包(您可以通过查看 this question 来了解其中的区别)。

要解决您的问题，请下载并安装 JDK(例如从 here 或从 here ，具体取决于您喜欢的版本)(如果您尚未安装) 。安装和/或解压后(如果您使用的是 linix，最好在 init 脚本中完成):

export JAVA_HOME=<path_to_the_extracted_jdk_directory>

在 Windows 上，创建一个名为 JAVA_HOME 的环境变量，并将值设置为安装目录的完整路径。

要验证 Maven 是否选择了正确的 Java 安装，您可以尝试

mvn -version

输出包含 Maven 所看到的 Java 安装的一行，例如:

...
Maven home: [path to maven]
Java version: 1.8.0_152, vendor: Oracle Corporation
Java home: /home/user/jdk/jdk1.8.0_152/jre
...