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/** * 通过JDK原生的GZIP压缩和解压缩文件 * @date 2017年12月29日  * @version V1.0 */public class GzipUtils {    public static byte[] gzip(byte[] data) throws Exception{    	ByteArrayOutputStream bos = new ByteArrayOutputStream();    	GZIPOutputStream gzip = new GZIPOutputStream(bos);    	gzip.write(data);    	gzip.finish();    	gzip.close();    	byte[] ret = bos.toByteArray();    	bos.close();    	return ret;    }        public static byte[] ungzip(byte[] data) throws Exception{    	ByteArrayInputStream bis = new ByteArrayInputStream(data);    	GZIPInputStream gzip = new GZIPInputStream(bis);    	byte[] buf = new byte[1024];    	int num = -1;    	ByteArrayOutputStream bos = new ByteArrayOutputStream();    	while((num = gzip.read(buf, 0 , buf.length)) != -1 ){    		bos.write(buf, 0, num);    	}    	gzip.close();    	bis.close();    	byte[] ret = bos.toByteArray();    	bos.flush();    	bos.close();    	return ret;    }        public static void main(String[] args) throws Exception{		    	//读取文件    	String readPath = System.getProperty("user.dir") + File.separatorChar + "sources" +  File.separatorChar + "006.jpg";        File file = new File(readPath);        //直接将文件io流一次性读到byte数组中        FileInputStream in = new FileInputStream(file);          byte[] data = new byte[in.available()];          in.read(data);          in.close();                  System.out.println("文件原始大小:" + data.length);        //测试压缩                byte[] ret1 = GzipUtils.gzip(data);        System.out.println("压缩之后大小:" + ret1.length);                byte[] ret2 = GzipUtils.ungzip(ret1);        System.out.println("还原之后大小:" + ret2.length);                //写出文件        String writePath = System.getProperty("user.dir") + File.separatorChar + "receive" +  File.separatorChar + "006.jpg";        FileOutputStream fos = new FileOutputStream(writePath);        //输出流直接输出字节数组        fos.write(ret2);        fos.close();    	    	    		}            }

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