数据库字段内容的压缩算法

package cn.ljz;

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

public class StringZip{
	public static String zipString(String str){
		try{
			ByteArrayOutputStream bos = null;
			GZIPOutputStream os = null;
			byte[] bs = null;
			try{
				bos = new ByteArrayOutputStream();
				os = new GZIPOutputStream(bos);
				os.write(str.getBytes());
				os.close();
				bos.close();
				bs = bos.toByteArray();
				return new String(bs,"iso-8859-1");
				
			}finally{
				bs = null;
				bos = null;
				os = null;
			}
		}catch(Exception ex){
			return str;
		}
	}
	
	public static String unzipString(String str){
		ByteArrayInputStream bis = null;
		ByteArrayOutputStream bos = null;
		GZIPInputStream is = null;
		byte[] buf = null;
		try{
			bis = new ByteArrayInputStream(str.getBytes("ISO-8859-1"));
			bos = new ByteArrayOutputStream();
			is = new GZIPInputStream(bis);
			buf = new byte[1024];
			int len;
			while((len=is.read(buf))!=-1){
				bos.write(buf,0,len);
			}
			is.close();
			bis.close();
			bos.close();
			return new String(bos.toByteArray());
			
		}catch(Exception ex){
			return str;
		}finally{
			bis = null;
			bos = null;
			is = null;
			buf = null;
		}
		
	}
}