mkdir FirstJar #建立FirstJar文件夹
javac -classpath ${HADOOP_HOME}/hadoop-${VERSION}-core.jar -d FirstJar WordCount.java #编译生成.class 文件，存放到FirstJar文件夹中
jar -cvf wordcount.jar -C FirstJar/ . #将FirstJar中的文件打包成wordcount.jar文件
hadoop jar wordcount.jar WordCount input output #执行命令