单独编译运行hadoop自带wordcount例子
1、首先要找到wordcount的源代码，在http://svn.apache.org/repos/asf/hadoop/中，用svn客户端check out下来，找到svn.apache.org_repos_asf\hadoop\hadoop-mapreduce-project\hadoop-mapreduce-examples\src\main\java\org\apache\hadoop\examples\WordCount.java
2、创建文件夹并且把wordcount文件拷出来：
mkdir?playground
mkdir?playground/src
mkdir?playground/classes
cp?src/examples/org/apache/hadoop/examples/WordCount.java?playground/src/WordCount.java
3、在hadoop框架中编译和执行这个副本
javac?-classpath?hadoop-core-1.0.1.jar:lib/commons-cli-1.2.jar?-d?playground/classes/?playground/src/WordCount.java
?
jar?-cvf?playground/wordcount.jar?-C?playground/classes/?.
?
