Hadoop压缩与解压代码,Java代码库,德仔网

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【Java】 Hadoop压缩与解压
作者: / 发布于2016/11/23/ 469
import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.URI;

 

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FSDataInputStream;

import org.apache.hadoop.fs.FSDataOutputStream;

import org.apache.hadoop.fs.FileSystem;

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.io.compress.CompressionOutputStream;

import org.apache.hadoop.util.ReflectionUtils;

 

public class CodecTest {

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

        compress("org.apache.hadoop.io.compress.BZip2Codec");

//        compress("org.apache.hadoop.io.compress.GzipCodec");

//        compress("org.apache.hadoop.io.compress.Lz4Codec");

//        compress("org.apache.hadoop.io.compress.SnappyCodec");

        // uncompress("text");

        // uncompress1("hdfs://master:9000/user/hadoop/text.gz");

    }

 

    // 压缩文件

    public static void compress(String codecClassName) throws Exception {

        Class<?> codecClass = Class.forName(codecClassName);

        Configuration conf = new Configuration();

         

        FileSystem fs = FileSystem.get(conf);

        CompressionCodec codec = (CompressionCodec) ReflectionUtils.newInstance(codecClass, conf);

        //输入和输出均为hdfs路径

        FSDataInputStream in = fs.open(new Path("/test.log"));

        FSDataOutputStream outputStream = fs.create(new Path("/test1.bz2"));

         

        System.out.println("compress start !");

         

        // 创建压缩输出流

        CompressionOutputStream out = codec.createOutputStream(outputStream);

        IOUtils.copyBytes(in, out, conf);

        IOUtils.closeStream(in);

        IOUtils.closeStream(out);

        System.out.println("compress ok !");

    }

 

    // 解压缩

    public static void uncompress(String fileName) throws Exception {

        Class<?> codecClass = Class

                .forName("org.apache.hadoop.io.compress.GzipCodec");

        Configuration conf = new Configuration();

        FileSystem fs = FileSystem.get(conf);

        CompressionCodec codec = (CompressionCodec) ReflectionUtils

                .newInstance(codecClass, conf);

        FSDataInputStream inputStream = fs

                .open(new Path("/user/hadoop/text.gz"));

        // 把text文件里到数据解压，然后输出到控制台

        InputStream in = codec.createInputStream(inputStream);

        IOUtils.copyBytes(in, System.out, conf);

        IOUtils.closeStream(in);

    }

 

    // 使用文件扩展名来推断二来的codec来对文件进行解压缩

    public static void uncompress1(String uri) throws IOException {

        Configuration conf = new Configuration();

        FileSystem fs = FileSystem.get(URI.create(uri), conf);

 

        Path inputPath = new Path(uri);

        CompressionCodecFactory factory = new CompressionCodecFactory(conf);

        CompressionCodec codec = factory.getCodec(inputPath);

        if (codec == null) {

            System.out.println("no codec found for " + uri);

            System.exit(1);

        }

        String outputUri = CompressionCodecFactory.removeSuffix(uri,

                codec.getDefaultExtension());

        InputStream in = null;

        OutputStream out = null;

        try {

            in = codec.createInputStream(fs.open(inputPath));

            out = fs.create(new Path(outputUri));

            IOUtils.copyBytes(in, out, conf);

        } finally {

            IOUtils.closeStream(out);

            IOUtils.closeStream(in);

        }

    }

 

}
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