public static void main(String[] args) throws IOException {　　　　　

　　　　　Configuration conf = new Configuration();

        FileSystem fs = FileSystem.get(conf);

        boolean tag=fs.exists(new Path(args[0]));

        String ftag=tag?"exist":"not exist";

        logger.info("===>the HDFS File :"+ args[0] +"is "+ftag);

        InputStream in=fs.open(new Path(args[0]));

　　　　//核心转换部分

        CompressionCodecFactory factory = new CompressionCodecFactory(conf);

        CompressionCodec codec = factory.getCodec(new Path(args[0]));

        CompressionInputStream compin=codec.createInputStream(in);

        BufferedReader br= new BufferedReader(new InputStreamReader(compin));

        String line="";

        while((line=br.readLine())!=null){

           //TODO

        }

        //TODO 关闭流

}