javac -classpath /opt/hadoop-1.2.1/hadoop-core-1.2.1.jar:/opt/hadoop-1.2.1/lib/commons-cli-1.2.jar -d word_count_class/WordCount.java javac: not a directory: word_count_class/WordCount.java Usage: javac
use -help for a list of possible options 什么意思？不存在那个目录