java - 无法运行Wordcount JAR文件

Question

hduser@ubuntu:~/Desktop$ hadoop jar wc.jar /usr/local/hadoop/input/sample.txt /usr/local/hadoop/output
Warning: $HADOOP_HOME is deprecated.

Exception in thread "main" java.lang.ClassNotFoundException: /usr/local/hadoop/input/sample/txt
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:274)
at org.apache.hadoop.util.RunJar.main(RunJar.java:153)

尝试使用Java 1.7和hadoop 1.2.1运行wordcount程序。

Answer 1

您已经告诉hadoop您的主类是“/usr/local/hadoop/input/sample.txt”

 jar

Runs a jar file. Users can bundle their Map Reduce code in a jar file and execute it using this command.

Usage: hadoop jar <jar> [mainClass] args... 

您需要在Java代码中使用它来设置jar类名称

job.setJarByClass(WordCount.class);