1,写一个java代码。*.java.(这里从example 拷贝一个过来作为测试)
cp src/examples/org/apache/hadoop/examples/WordCount.java .
2,编译文件
javac -classpath hadoop-core-1.2.1.jar -d FirstJar WordCount.java
(这里出错。换用下面的命令:)
javac -classpath hadoop-core-1.2.1.jar:lib/commons-cli-1.2.jar -d FirstJar WordCount.java
3,编译完成后,对编译好的class打包
jar -cvf WordCount.jar -C FirstJar/ .
ls
bin/hadoop dfs -ls (这里已经上传给HDFS in 文件
4.运行。
bin/hadoop jar WordCount.jar org.apache.hadoop.examples.WordCount in output
bin/hadoop dfs -ls
bin/hadoop dfs -rmr output /删除文件/