使用gzip技术对文件做压缩和解压缩

悠悠 2022-05-13 05:04 234阅读 0赞

gzip工具类：

package cn.utils;
    
    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;
    
    /**
     * Title: GzipUtils 
     * @date 2018年9月5日
     * @version V1.0 
     * Description:将文件或数据按照gzip方式压缩和解压缩
     */
    @SuppressWarnings("all")
    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（数据）
    	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);
    	}
    }

上传文件并压缩：

public R uploadFile(MultipartFile[] files, int type, String describe) {
        BufferedOutputStream stream = null;
    	for (int i = 0; i < files.length; i++) {
    		MultipartFile file = files[i];
    		if (!file.isEmpty()) {
    			// 获取文件名
    			String filename = file.getOriginalFilename();
    			if (filename.contains(".jsp")) {
    				return R.error("您上传的文件格式不正确，请重新上传");
    			}
    			String folderName = "D://" + type + "/" + TimeUtils.toYM();
    			File folderFile = new File(folderName);
    			// 判断文件夹是否存在 不存在
    			if (!folderFile.exists()) {
    				folderFile.mkdirs();
    			}
    			// 新文件名
    			String newFileName = IDUtils.genImageName()
    					+ filename.substring(filename.indexOf("."), filename.length());
    			String newFile = folderFile + "/" + newFileName;
    			File departFile = new File(newFile);
    			try {
    				if (!departFile.exists()) {
    					departFile.createNewFile();
    				}
    				// 压缩文件
    				byte[] bytes = GzipUtils.compress(file.getBytes());
    				stream = new BufferedOutputStream(new FileOutputStream(new File(newFile)));
    				stream.write(bytes);
    			} catch (Exception e) {
    				return R.error("服务器繁忙，请稍后重试");
    			} finally {
    				try {
                           if(stream!=null){
                               stream.close();
                           }
    				} catch (IOException e) {
    					e.printStackTrace();
    				}
    			}
    		} else {
    			return R.result(400, "上传文件不能为空");
    		}
    	}
    		return R.ok("上传成功");
    	}

解压缩并下载文件：

public R downloadFile(HttpServletResponse response, int fileId) {
    	response.setHeader("content-type", "application/octet-stream");
    	response.setContentType("application/octet-stream");
        String fileUrl="D://"+fileId;
    	response.setHeader("Content-Disposition",
    			"attachment;filename=" + fileUrl.substring(fileUrl.lastIndexOf("/") + 1, fileUrl.length()));
    	File file = new File(fileUrl);
    	if (!file.exists()) {
    		return R.error("文件不存在");
    	}
    	FileInputStream fis = null;
    	ByteArrayOutputStream bos = null;
    	try {
    		// 将file文件转成bytes 进行解压缩
    		fis = new FileInputStream(file);
    		bos = new ByteArrayOutputStream(fis.available());
    		byte[] b = new byte[1024];
    		int len = -1;
    		while ((len = fis.read(b)) != -1) {
    			bos.write(b, 0, len);
    		}
    		// 进行解压缩
    		byte[] bytes = GzipUtils.uncompress(bos.toByteArray());
    		response.getOutputStream().write(bytes);
    		return R.ok("下载文件成功");
    	} catch (Exception e) {
    		e.printStackTrace();
    		return R.error("文件下载失败");
    	} finally {
    	    try {
                    if(fis!=null){
                        fis.close();
                    }
    	        if(bos!=null){
                        bos.close();
                    }
    	    } catch (IOException e) {
    		    e.printStackTrace();
    	    }
            }
        }else {
    		    return R.error("文件不存在");
    	      }	
        }