java Gzip压缩与解压

package waf.util.zip;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class GZip {

    public static void main(String[] args) {

    }

    public static String uncompress(byte[] src, String charset) 
    {
        String ret="";
        ByteArrayInputStream bais=new ByteArrayInputStream(src);
        ret=uncompress(bais,charset);
        return ret;
    }
    public static String uncompress(ByteArrayInputStream in, String charset) {
        try 
        {
            GZIPInputStream gInputStream = new GZIPInputStream(in);
            byte[] by = new byte[1024];
            StringBuffer strBuffer = new StringBuffer();
            int len = 0;
            while ((len = gInputStream.read(by)) != -1) {
                strBuffer.append(new String(by, 0, len, charset));
            }
            return strBuffer.toString();
        }catch (IOException e) 
        {
            e.printStackTrace();
        }
        return null;
    }

    public static byte[] compress(String str, String charset) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try {
            GZIPOutputStream gOutputStream = new GZIPOutputStream(out);
            gOutputStream.write(str.getBytes(charset));
            gOutputStream.finish();
            gOutputStream.close();
            out.flush();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return out.toByteArray();

    }
}