编译Hadoop字数教程- hadoop 2.6.3

Question

下面是我的系统配置: windows8.1、vmware v12、2个centOS VM。我已经在我的VM上安装了hadoop，一个作为主服务器，另一个作为slave1。服务在两个节点上正确地启动和运行。

我想编译我的第一个mapreduce程序，wordcount教程:我试图使用以下方法编译：

[hadoop@master ~]$ javac -classpath $HADOOP_HOME/share/common/hadoop-common-2.6.3.jar:$HADOOP-HOME/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.6.3.jar:$HADOOP_HOME/share/common/lib/common-cli-1.2.jar -d /home/hadoop *.java

但我得到的答案是：

WordCount.java:4: error: package org.apache.hadoop.conf does not exist
import org.apache.hadoop.conf.Configuration;
                             ^
WordCount.java:5: error: package org.apache.hadoop.fs does not exist
import org.apache.hadoop.fs.Path;
                           ^
WordCount.java:6: error: package org.apache.hadoop.io does not exist
import org.apache.hadoop.io.IntWritable;
                           ^
WordCount.java:7: error: package org.apache.hadoop.io does not exist
import org.apache.hadoop.io.Text;
                           ^
WordCount.java:8: error: package org.apache.hadoop.mapreduce does not exist
(.
.
.)                                       ^
  symbol:   class Path
  location: class WordCount
WordCount.java:58: error: cannot find symbol
    FileOutputFormat.setOutputPath(job, new Path(args[1]));
    ^
  symbol:   variable FileOutputFormat
  location: class WordCount
40 errors

我在谷歌上搜索，每个人都说这是$CLASSPATH的功劳。

这是我的/etc/bashrc文件：

export JAVA_HOME=/opt/jdk
export JRE_HOME=/opt/jdk/jre
export PATH=$PATH:/opt/jdk/bin:/opt/jdk/jre/bin
export HADOOP_CLASSPATH=$JAVA_HOME/lib/tools.jar
export HADOOP_HOME=/opt/hadoop/
export CLASSPATH=$CLASSPATH:$HADOOP_HOME/share/common/hadoop-common-2.6.3.jar:$HADOOP-HOME/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.6.3.jar:$HADOOP_HOME/share/common/lib/common-cli-1.2.jar

知道我为什么会犯这个错误吗？我看没问题..。:(

Answer 1

根据文档，您可以执行以下操作(在我的系统和工作上进行测试)

• export HADOOP_CLASSPATH=${JAVA_HOME}/lib/tools.jar
• 使用$HADOOP_HOME/bin/hadoop com.sun.tools.javac.Main WordCount.java并最终创建jar
• jar cf wc.jar WordCount*.class

链接到这里的官方文档