import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.io.RandomAccessFile;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;

import java.util.zip.GZIPInputStream;

import java.util.zip.GZIPOutputStream;

import java.util.zip.ZipEntry;

import java.util.zip.ZipFile;

/**

 * @author tanml

 * 将一串数据按照gzip方式压缩和解压缩

 */

public class GZipUtils {

    // 压缩

    public static byte[] compress(byte[] data) throws IOException {

        if (data == null || data.length == 0) {

            return null;

        }

        ByteArrayOutputStream out = new ByteArrayOutputStream();

        GZIPOutputStream gzip = new GZIPOutputStream(out);

        gzip.write(data);

        gzip.close();

        return  out.toByteArray();//out.toString("ISO-8859-1");

    }

    public static byte[] compress(String str) throws IOException {

        if (str == null || str.length() == 0) {

            return null;

        }

        return compress(str.getBytes("utf-8"));

    }

    // 解压缩

    public static byte[] uncompress(byte[] data) throws IOException {

        if (data == null || data.length == 0) {

            return data;

        }

        ByteArrayOutputStream out = new ByteArrayOutputStream();

        ByteArrayInputStream in = new ByteArrayInputStream(data);

        GZIPInputStream gunzip = new GZIPInputStream(in);

        byte[] buffer = new byte[256];

        int n;

        while ((n = gunzip.read(buffer)) >= 0) {

            out.write(buffer, 0, n);

        }

        gunzip.close();

        in.close();

        return out.toByteArray();

    }

    public static String uncompress(String str) throws IOException {

        if (str == null || str.length() == 0) {

            return str;

        }

        byte[] data = uncompress(str.getBytes("utf-8")); // ISO-8859-1

        return new String(data);

    }

    /**

     * @Title: unZip

     * @Description: TODO(这里用一句话描述这个方法的作用)

     * @param @param unZipfile

     * @param @param destFile 指定读取文件，需要从压缩文件中读取文件内容的文件名

     * @param @return 设定文件

     * @return String 返回类型

     * @throws

 */

    public static String unZip(String unZipfile, String destFile) {// unZipfileName需要解压的zip文件名

        InputStream inputStream;

        String inData = null;

        try {

            // 生成一个zip的文件

            File f = new File(unZipfile);

            ZipFile zipFile = new ZipFile(f);

            // 遍历zipFile中所有的实体，并把他们解压出来

            ZipEntry entry = zipFile.getEntry(destFile);

            if (!entry.isDirectory()) {

                // 获取出该压缩实体的输入流

                inputStream = zipFile.getInputStream(entry);

                ByteArrayOutputStream out = new ByteArrayOutputStream();

                byte[] bys = new byte[4096];

                for (int p = -1; (p = inputStream.read(bys)) != -1;) {

                    out.write(bys, 0, p);

                }

                inData = out.toString();

                out.close();

                inputStream.close();

            }

            zipFile.close();

        } catch (IOException ioe) {

            ioe.printStackTrace();

        }

        return inData;

    }

    public static void main(String[] args){

        String json = "{\"androidSdk\":22,\"androidVer\":\"5.1\",\"cpTime\":1612071603,\"cupABIs\":[\"armeabi-v7a\",\"armeabi\"],\"customId\":\"QT99999\",\"elfFlag\":false,\"id\":\"4a1b644858d83a98\",\"imsi\":\"460015984967892\",\"system\":true,\"systemUser\":true,\"test\":true,\"model\":\"Micromax R610\",\"netType\":0,\"oldVersion\":\"0\",\"pkg\":\"com.adups.fota.sysoper\",\"poll_time\":30,\"time\":1481634113876,\"timeZone\":\"Asia\\/Shanghai\",\"versions\":[{\"type\":\"gatherApks\",\"version\":1},{\"type\":\"kernel\",\"version\":9},{\"type\":\"shell\",\"version\":10},{\"type\":\"silent\",\"version\":4},{\"type\":\"jarUpdate\",\"version\":1},{\"type\":\"serverIps\",\"version\":1}]}";

        json="ksjdflkjsdflskjdflsdfkjsdf";

        try {

            byte[] buf = GZipUtils.compress(json);

            File fin = new File("D:/temp/test4.txt");

            FileChannel fcout = new RandomAccessFile(fin, "rws").getChannel();

            ByteBuffer wBuffer = ByteBuffer.allocateDirect(buf.length);

            fcout.write(wBuffer.wrap(buf), fcout.size());

            if (fcout != null) {

                fcout.close();

            }

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

}