Hadoop文件解压缩

Class
org.apache.hadoop.io.compress .CompressionCodecFactory
A factory that will find the correct codec for a given filename.

Method
CompressionCodec getCodec(Path file)
Find the relevant compression codec for the given file based on its filename suffix.
获得这个压缩数据文件采用哪种压缩数据算法。

package Compress;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IOUtils;import org.apache.hadoop.io.compress.CompressionCodec;import org.apache.hadoop.io.compress.CompressionCodecFactory;import org.apache.hadoop.io.compress.CompressionInputStream;import org.apache.hadoop.mapreduce.Job;/** * 解压缩 * @author liguodong */public class Decompression {    final static String file = "/liguodong/data.gz";    public static void main(String[] args) throws IOException {        Configuration conf = new Configuration();         Job job = Job.getInstance(conf, "DeCodec");          //打包运行必须执行的方法        job.setJarByClass(Decompression.class);        CompressionCodecFactory codecFactory = new CompressionCodecFactory(conf);        //返回一个解压缩的实例        CompressionCodec codec = codecFactory.getCodec(new Path(file));        //返回被算法解压了的输入流        CompressionInputStream inputStream = codec.createInputStream                (new FileInputStream(new File(file)));        //将输入流文件写出到去除了扩展名的文件        FileOutputStream outputStream = new FileOutputStream                (new File(codecFactory.removeSuffix(file, codec.getDefaultExtension())));        IOUtils.copyBytes(inputStream, outputStream, conf);    }}

打成jar包：Decodec.jar

[root@master liguodong]# yarn jar Decodec.jar15/06/05 21:54:25 INFO zlib.ZlibFactory: Successfully loaded & initialized native-zlib library[root@master liguodong]# ll总用量 524824-rw-r--r-- 1 root root      1492 6月   5 19:47 codec.jar-rw-r--r-- 1 root root 536870912 6月   5 21:54 data-rw-r--r-- 1 root root    521844 6月   5 21:40 data.gz