数据压缩解压缩（zip）

网络上传输数据大部分都需要压缩数据后传递，常见的有zip方式压缩/解压缩

/**  
	 * 数据压缩  
	 * @param data  
	 * @return  
	 */  
	public static byte[] dataGZip(byte[] data) 
	{   
		ByteArrayInputStream bais = null;
	    GZIPOutputStream gos = null;   
	    ByteArrayOutputStream baos = null;
	    try 
	    {   
	    	bais = new ByteArrayInputStream(data);
	        baos = new ByteArrayOutputStream();   
	        gos = new GZIPOutputStream(baos);   
	           
	        byte[] buf = new byte[1024*1024];   
	        int num;   
	        while ((num = bais.read(buf)) != -1) {   
	            gos.write(buf, 0, num);   
	        }   
	        gos.finish();   
	        gos.flush();   
	        byte[] output = baos.toByteArray();  
	        
	        return output;   
	    } catch (IOException e) 
	    {   
	    	log.error(e.getMessage(), e);
	    } finally
	    {
	    	if (null != gos)
	    	{
	    		try
				{
					gos.close();
				} catch (IOException e)
				{
				}
	    	}
	    	if (null != baos)
	    	{
	    		try
				{
					baos.close();
				} catch (IOException e)
				{
				}
	    	}
	    	if (null != bais)
	    	{
	    		try
				{
	    			bais.close();
				} catch (IOException e)
				{
				}
	    	}
	    }
	    return null;   
	}   

/**  
	 * 数据解压缩  
	 * @param data  
	 * @return  
	 */  
	public static byte[] dataUnGZip(byte[] data)
	{   
		ByteArrayInputStream bais = null;
		GZIPInputStream gis = null;
		ByteArrayOutputStream baos = null;
	    try 
	    {   
	        bais = new ByteArrayInputStream(data);   
	        gis = new GZIPInputStream(bais);   
	        baos = new ByteArrayOutputStream();   
	        byte[] buf = new byte[1024*1024];   
	        int num;   
	        while((num=gis.read(buf))!=-1)
	        {   
	            baos.write(buf, 0, num);   
	        }   
	        byte[] ret = baos.toByteArray();   
	        
	        return ret;   
	    } catch (IOException e) 
	    {   
	        log.error(e.getMessage(), e);
	    } finally
	    {
	    	if (null != baos)
	    	{
	    		try
				{
					baos.close();
				} catch (IOException e)
				{
				}   
	    	}
	    	if (null != gis)
	    	{
	    		try
				{
					gis.close();
				} catch (IOException e)
				{
				}
	    	}
	    	if (null != bais)
	    	{
	    		try
				{
					bais.close();
				} catch (Exception e)
				{
				}
	    	}
	    }
	    return null;   
	}