压缩文件——干货代码分享

淡淡的烟草味﹌ 2024-03-17 13:03 56阅读 0赞

## 1.背景 ##

###### 最近写接口遇到通过FTP服务器发送文件的需求，文件内容需加密并压缩，故记录一下，提供已经测试通过的代码。 ######

## 2.代码 ##

package com.example.demo.utils;
    
    import lombok.extern.slf4j.Slf4j;
    
    import java.io.*;
    import java.util.zip.GZIPOutputStream;
    
    @Slf4j
    public class GZipUtils {
        /**
        * compress the file
        * @param inBoundFilePath the file need to compress
        * @return the uncompressed file's absolute path
        * */
        public static String doCompressFile(String inBoundFilePath) {
            String newFileName;
            File zipFile;
            /*auto-closeable*/
            try(FileInputStream inputStream = new FileInputStream(inBoundFilePath);
            GZIPOutputStream gzipOutputStream = new GZIPOutputStream(new FileOutputStream(inBoundFilePath + ".gz"))){
                log.debug("... opening ...filepath{} ",inBoundFilePath);
                log.debug("... compressing ...");
                byte[] bytes = new byte[1024];
                int readLength ;
                int fileLength = 0;
                while(( readLength = inputStream.read(bytes)) > 0) {
                    gzipOutputStream.write(bytes,0,fileLength);
                    fileLength+=readLength;
                }
                gzipOutputStream.finish();
                gzipOutputStream.flush();
                log.debug("compress task finish");
                log.debug("original file size {}",fileLength);
                zipFile = new File(inBoundFilePath + ".gz");
                log.debug("compressed file size {}",zipFile.length());
            } catch (FileNotFoundException e) {
                log.error("filename:{} doesn't exists",inBoundFilePath);
                log.error(e.getMessage());
                return null;
            } catch (IOException e) {
                log.error(e.getMessage());
                return null;
            }
    
            /*reName the filename with file size suffix .It's required by the requirements doc */
            String fileLength = String.format("%08d",Integer.parseInt(String.valueOf(zipFile.length())));
            newFileName = inBoundFilePath + fileLength;
            if (reName(inBoundFilePath + ".gz",newFileName)){
                return newFileName;
            } else {
                log.error("error renaming");
                return null;
            }
        }
        /**
         * rename the file
         * @param absolutePathName the filename with absolute path prefix
         * @param newFilename renamed filename
         * @return boolean
         * */
        private static boolean reName(String absolutePathName,String newFilename) {
            File file = new File(absolutePathName);
            if (file.exists()) {
                return file.renameTo(new File(newFilename));
            }
            log.error("file doesn't exists ");
            return false ;
        }
    }

测试，一个文档

![ced2297f197b4294959485facf9b2137.png][]

大小![67119f3b82f44670b468d129b9a7b85b.png][]

测试类

![bb945fec0b0b41ed9eda9e6281801f91.png][]

测试结果，控制台显示

![726c96c9f48945849cdc82cf9865a9f3.png][]

核对压缩后文件的实际大小

![35264d725df2403bae2f428edeca9ea0.png][]

解压缩软件打开后

![c625c6a1b23b4cf68695566800817ffd.png][]

[ced2297f197b4294959485facf9b2137.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/1d7f140c6f9a4ef5aca686f6f6732e49.png
[67119f3b82f44670b468d129b9a7b85b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/729cc5dd0fdb4970991396a7983a5722.png
[bb945fec0b0b41ed9eda9e6281801f91.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/a3c0c04b012e4f8881426b7a050e334e.png
[726c96c9f48945849cdc82cf9865a9f3.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/07a31d5b20ad4e87bd2e9dd142be1063.png
[35264d725df2403bae2f428edeca9ea0.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/85ed7c905f6740c4aa83df586cd77fb5.png
[c625c6a1b23b4cf68695566800817ffd.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/f4d49f04c5fd4691b8201159013c5b78.png