輸入命令：hadoop jar word_count_class/wordcount.jar WordCount input_wordcount output_wordcount

控制臺輸出：Exception in thread "main" java.lang.NoClassDefFoundError: WordCount (wrong name: wordcount/WordCount)

? ? ? ? at java.lang.ClassLoader.defineClass1(Native Method)

? ? ? ? at java.lang.ClassLoader.defineClass(ClassLoader.java:763)

? ? ? ? at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

? ? ? ? at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)

? ? ? ? at java.net.URLClassLoader.access$100(URLClassLoader.java:74)

? ? ? ? at java.net.URLClassLoader$1.run(URLClassLoader.java:369)

? ? ? ? at java.net.URLClassLoader$1.run(URLClassLoader.java:363)

? ? ? ? at java.security.AccessController.doPrivileged(Native Method)

? ? ? ? at java.net.URLClassLoader.findClass(URLClassLoader.java:362)

? ? ? ? at java.lang.ClassLoader.loadClass(ClassLoader.java:424)

? ? ? ? at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

? ? ? ? at java.lang.Class.forName0(Native Method)

? ? ? ? at java.lang.Class.forName(Class.java:348)

? ? ? ? at org.apache.hadoop.util.RunJar.main(RunJar.java:153)