HadoopFileReader.java 文件源码

public InputStream openFile(Path path) throws IOException {
        CompressionCodec codec=compressionCodecs.getCodec(path);
    FSDataInputStream fileIn=fs.open(path);
    // check if compressed
    if (codec==null) { // uncompressed
    LOG.debug("Reading from an uncompressed file \""+path+"\"");
        return fileIn;
    } else { // compressed
        Decompressor decompressor = CodecPool.getDecompressor(codec);
        this.openDecompressors.add(decompressor); // to be returned later using close
        if (codec instanceof SplittableCompressionCodec) {
            LOG.debug("Reading from a compressed file \""+path+"\" with splittable compression codec");
            long end = fs.getFileStatus(path).getLen(); 
                return ((SplittableCompressionCodec)codec).createInputStream(fileIn, decompressor, 0, end,SplittableCompressionCodec.READ_MODE.CONTINUOUS);
            } else {
            LOG.debug("Reading from a compressed file \""+path+"\" with non-splittable compression codec");
                return codec.createInputStream(fileIn,decompressor);
            }
    }
}