将数据按照gzip当时解压的工具类

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();

}

}

}