利用hadoop streaming框架，帮助我们在map和reduce之间传递数据，通过stdin和stdout.
http://wenku.baidu.com/link?url=R1vj6NWV5nv_aVI8P0G5SNzxOyaDsffGeOJrRT6iA9iYHry3w60hJ9CVAtS1iRkh7IOYEuGozIqAZubfXybzf1URxTEY7a2gY9L3LTZQ0Wq
