java工具类——java将一串数据按照gzip方式压缩和解压缩

       我要整理在工作中用到的工具类分享出来，也方便自己以后查阅使用，这些工具类都是我自己实际工作中使用的

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();
		}
	}
}