不多說，直接上乾貨！

 問題詳情

　　執行出現log4j的問題

"C:\Program Files\Java\jdk1.8.0_66\bin\java" -Didea.launcher.port=7533 "-Didea.launcher.bin.path=D:\SoftWare\IntelliJ IDEA\IntelliJ IDEA Community Edition 2016.1.4\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_66\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_66\jre\lib\rt.jar;D:\Code\IntelliJIDEACode\HadoopSparkMllibAction\target\classes;D:\SoftWare\maven\repository\org\scala-lang\scala-library\2.10.4\scala-library-2.10.4.jar;C:\Program Files\Java\jdk1.8.0_66\jre\..\lib\tools.jar;D:\SoftWare\IntelliJ IDEA\IntelliJ IDEA Community Edition 2016.1.4\lib\idea_rt.jar
 
" com.intellij.rt.execution.application.AppMain zhouls.bigdata.chapter10.RunWordCount
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Logger
    at zhouls.bigdata.chapter10.RunWordCount$.main(RunWordCount.scala:12)
    at zhouls.bigdata.chapter10.RunWordCount.main(RunWordCount.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:
 
62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Logger
    at java.net.URLClassLoader.findClass(URLClassLoader.java:
 
381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 7 more

Process finished with exit code 1

 解決辦法

 　　在專案的pom.xml裡新增如下的配置資訊

<dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.16</version>
      <scope>compile</scope>
 </dependency>

 　　當然，這版本，大家也可以選擇個最新的穩定版本，我這裡僅僅是個參考。