缺少Hadoop 2.2.0 jar文件

Question

我已經安裝了hadoop-2.2.0，並試圖運行它附帶的mapreduce示例代碼。 但是，每次使用ClassNotFoundException都會失敗，而我發現的原因是hadoop.sh文件中設置的hadoop.sh 。 以下是sh文件中提供的內容，安裝中未捆綁任何類文件。 我確實看到它們出現在源代碼中。

if [ "$COMMAND" = "fs" ] ; then
  CLASS=org.apache.hadoop.fs.FsShell
elif [ "$COMMAND" = "version" ] ; then
  CLASS=org.apache.hadoop.util.VersionInfo
elif [ "$COMMAND" = "jar" ] ; then
  CLASS=org.apache.hadoop.util.RunJar
elif [ "$COMMAND" = "checknative" ] ; then
  CLASS=org.apache.hadoop.util.NativeLibraryChecker
elif [ "$COMMAND" = "distcp" ] ; then
  CLASS=org.apache.hadoop.tools.DistCp
  CLASSPATH=${CLASSPATH}:${TOOL_PATH}
elif [ "$COMMAND" = "daemonlog" ] ; then
  CLASS=org.apache.hadoop.log.LogLevel
elif [ "$COMMAND" = "archive" ] ; then
  CLASS=org.apache.hadoop.tools.HadoopArchives
  CLASSPATH=${CLASSPATH}:${TOOL_PATH}
elif [[ "$COMMAND" = -*  ]] ; then
    # class and package names cannot begin with a -
    echo "Error: No command named \`$COMMAND' was found. Perhaps you meant \`hadoop ${COMMAND#-}'"
    exit 1
else
  CLASS=$COMMAND

這是錯誤：

Exception in thread "main" java.lang.NoClassDefFoundError: org.apache.hadoop.util.RunJar
   at gnu.java.lang.MainThread.run(libgcj.so.13)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.util.RunJar not found in gnu.gcj.runtime.SystemClassLoader{urls=[file:/usr/local/hadoop-2.2.0/etc/hadoop/,file:/usr/local/hadoop-2.2.0/share/hadoop/hdfs/], parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}}
   at java.net.URLClassLoader.findClass(libgcj.so.13)
   at gnu.gcj.runtime.SystemClassLoader.findClass(libgcj.so.13)
   at java.lang.ClassLoader.loadClass(libgcj.so.13)
   at java.lang.ClassLoader.loadClass(libgcj.so.13)
   at gnu.java.lang.MainThread.run(libgcj.so.13)

Answer 1

我終於弄清楚了這個問題。 YARN（用於mapreduce）和DFS進程需要在后台運行才能運行任何hadoop作業。 我想念那些成為Hadoop的n00b的人。 要啟動這兩個進程，請在命令窗口中鍵入start-yarn和start-dfs 。 他們每個都啟動2個控制台窗口，並吐出很多診斷信息。