Hadoop系列修炼笔记12

核心内容：压缩和解压缩的代码

package com.shujuelin.hdfs.mr.compress;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.compress.*;
import org.apache.hadoop.util.ReflectionUtils;
import org.junit.Test;

import java.io.FileInputStream;
import java.io.FileOutputStream;

/**
 * 测试压缩
 */
public class TextCompress {

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

        Class[] zipClasses = {
                DeflateCodec.class,
                GzipCodec.class,
                BZip2Codec.class,
                Lz4Codec.class,
                SnappyCodec.class
        };

        for(Class c : zipClasses){
            //unzip(c);
            zip(c);
        }
    }

    /**
     * 压缩测试
     */
    public static void zip(Class codecClass) throws Exception {
        long start = System.currentTimeMillis();
        //实例化对象CompressionCodec：压缩编解码器
        CompressionCodec codec = (CompressionCodec) ReflectionUtils.newInstance(codecClass, new Configuration());
        //创建文件输出流,得到默认扩展名
        FileOutputStream fos = new FileOutputStream("/home/centos/zip/b" + codec.getDefaultExtension());
        //得到压缩流
        CompressionOutputStream zipOut = codec.createOutputStream(fos);
        IOUtils.copyBytes(new FileInputStream("/home/centos/zip/hadoop.txt"), zipOut, 1024);
        zipOut.close();
        System.out.println(codecClass.getSimpleName() + " : " + (System.currentTimeMillis() - start) );
    }

    /**
     * 解压缩
     */
    public static void unzip(Class codecClass) throws Exception {
        long start = System.currentTimeMillis();
        //实例化对象
        CompressionCodec codec = (CompressionCodec)ReflectionUtils.newInstance(codecClass, new Configuration());
        //创建文件输出流,得到默认扩展名
        FileInputStream fis = new FileInputStream("/home/centos/zip/b" + codec.getDefaultExtension());
        //得到压缩流
        CompressionInputStream zipIn = codec.createInputStream(fis);
        IOUtils.copyBytes(zipIn,new FileOutputStream("/home/centos/zip/hadoop" + codec.getDefaultExtension() + ".txt"), 1024);
        zipIn.close();
        System.out.println(codecClass.getSimpleName() + " : " + (System.currentTimeMillis() - start) );
    }
}