FTP服务器打包下载文件的步骤

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需求：从ftp服务器打包下载文件

解决步骤：1.从ftp服务器把各个文件下载到本地服务器(一般是安装tomcat的服务器，项目自己电脑跑的本地服务器就是自己电脑)指定目录中

2.在本地服务器打包下载好的文件夹打包，返回打包好的File zip

3.zip文件用流写入reponse，达到用户下载效果

准备文件：

// 封装所有需要打包下载的文件地址请求类public class DownloadPackageReq implements Serializable {// 本地服务器临时存放目录名(尽量唯一.eg:"menutree20200904112125")    private String localTempDirName; // 打包下载本地服务器文件夹名字private List downloadPackageListReqList; // 需要下载所有文件路径和名称}

// FTPClientUtils：ftp工具类public static FTPClientUtils init() {   FTPClientUtils ftp = new FTPClientUtils();   ftp.setHost(host);   ftp.setPort(port);   ftp.setUsername(username);   ftp.setPassword(password);   ftp.setBinaryTransfer(true);   ftp.setPassiveMode(false);   ftp.setEncoding("utf-8");   return ftp;}

/** * 下载一个远程文件到本地的指定文件 *  * @param remoteAbsoluteFile *            远程文件名(包括完整路径,eg:/MTL/test/menutree_attachment/file.xlsx) * @param localAbsoluteFile *            本地文件名(包括完整路径) * @param autoClose *            是否自动关闭当前连接 *  * @return 成功时，返回true，失败返回false * @throws Exception */public boolean get(String remoteAbsoluteFile, String localAbsoluteFile, boolean autoClose) throws Exception {   OutputStream output = null;   try {      output = new FileOutputStream(localAbsoluteFile);      return get(remoteAbsoluteFile, output, autoClose);   } catch (FileNotFoundException e) {      throw new Exception("local file not found.", e);   } finally {      try {         if (output != null) {            output.close();         }      } catch (IOException e) {         throw new Exception("Couldn't close FileOutputStream.", e);      }   }}

/** * 下载一个远程文件到指定的流 处理完后记得关闭流 *  * @param remoteAbsoluteFile * @param output * @param autoClose * @return * @throws Exception */public boolean get(String remoteAbsoluteFile, OutputStream output, boolean autoClose) throws Exception {   try {      FTPClient ftpClient = getFTPClient();      // 处理传输      return ftpClient.retrieveFile(remoteAbsoluteFile, output);   } catch (IOException e) {      throw new Exception("Couldn't get file from server.", e);   } finally {      if (autoClose) {         disconnect(); // 关闭链接      }   }}

第一步：

public File downloadMenuTreeAttachment(Integer menutreeId) throws Exception {    // 从数据库拿到menutreeId对应的所有文件地址List resourcesMenutreeLists = resourcesMenutreeListMapper.selExistingAttachment(menutreeId);DownloadPackageReq req = new DownloadPackageReq();if (CollectionUtils.isNotEmpty(resourcesMenutreeLists)) {req.setLocalTempDirName(resourcesMenutreeLists.get(0).getMenutreeName() + DateUtils.dateTimeNow());List dpList = new ArrayList<>();for(ResourcesMenutreeListVo temp : resourcesMenutreeLists) {DownloadPackageListReq dpReq = new DownloadPackageListReq();            // 文件名称，用来下载ftp服务器文件修改文件名(因为ftp文件都是uuid名称)String fileName = temp.getModuleName() + "_" + temp.getEngineerName();dpReq.setFileName(fileName);dpReq.setFileFtpUrl(temp.getMenutreeAttachment());dpList.add(dpReq);        }req.setDownloadPackageListReqList(dpList);    } else {req.setLocalTempDirName("空菜单树" + DateUtils.dateTimeNow());    }return ftpService.zipFiles(req);}

public File zipFiles(DownloadPackageReq req) throws Exception {HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();// 本地服务器暂存路径    String localTempDir = request.getSession().getServletContext().getRealPath("/") + req.getLocalTempDirName() + File.separator;logger.info("本地服务器暂存路径:" + localTempDir);File dir = new File(localTempDir);if ( ! dir.exists()) {dir.mkdir();    }if (CollectionUtils.isNotEmpty(req.getDownloadPackageListReqList())) {List downloadList = req.getDownloadPackageListReqList();FTPClientUtils ftp = FTPClientUtils.init();for(int i=0; i
第二步：
public class ZipUtil {private static Logger logger = Logger.getLogger(ZipUtil.class);/**     * 缓冲器大小     */    private static final int BUFFER = 512;/**     * 压缩方法 （可以压缩空的子目录）     *     * @param srcPath     压缩源路径     * @param zipFileName 目标压缩文件     * @return     */    public static File zip(String srcPath, String zipFileName) {ZipOutputStream zipOutputStream = null;InputStream inputStream = null;File outputZipFile = null;try {// 检查文件是否存在，是的话先删除            outputZipFile = new File(zipFileName);if (outputZipFile.exists()) {                outputZipFile.delete();            }File srcFile = new File(srcPath);List fileList = FileUtil.getAllFiles(srcFile);// 所有要压缩的文件            byte[] buffer = new byte[BUFFER];// 缓冲器            ZipEntry zipEntry = null;int readLength = 0;// 每次读出来的长度            zipOutputStream = new ZipOutputStream(new FileOutputStream(zipFileName));for (File file : fileList) {if (file.isFile()) {// 若是文件，则压缩这个文件                    zipEntry = new ZipEntry(getRelativePath(srcPath, file));                    zipEntry.setSize(file.length());                    zipEntry.setTime(file.lastModified());                    zipOutputStream.putNextEntry(zipEntry);                    inputStream = new BufferedInputStream(new FileInputStream(file));while ((readLength = inputStream.read(buffer, 0, BUFFER)) != -1) {                        zipOutputStream.write(buffer, 0, readLength);                    }                } else {// 若是目录（即空目录）则将这个目录写入zip条目                    zipEntry = new ZipEntry(getRelativePath(srcPath, file) + File.separator);                    zipOutputStream.putNextEntry(zipEntry);                }            } // end for        } catch (FileNotFoundException e) {logger.error("zip fail!", e);        } catch (IOException e) {logger.error("zip fail!", e);        } finally {close(inputStream);close(zipOutputStream);        }// 返回文件输出流        outputZipFile = new File(zipFileName);return outputZipFile;    }/**     * 关闭流     */    private static void close(Closeable c) {if (c == null)return;try {            c.close();        } catch (IOException e) {logger.error("close fail!", e);        }        c = null;    }/**     * 取相对路径 依据文件名和压缩源路径得到文件在压缩源路径下的相对路径     *     * @param dirPath 压缩源路径     * @param file     * @return 相对路径     */    public static String getRelativePath(String dirPath, File file) {File dir = new File(dirPath);String relativePath = file.getName();while (true) {            file = file.getParentFile();if (file == null) {break;            }if (file.equals(dir)) {break;            } else {                relativePath = file.getName() + "/" + relativePath;            }        } // end while        return relativePath;    }}
第三步：Controller控制器，Result是自己封装的返回类，可以自定义String之类的返回
public Result downloadMenuTreeAttachment(Integer menutreeId, HttpServletResponse response) {BufferedInputStream bis = null;OutputStream os = null;try {File file = resourcesMenutreeListService.downloadMenuTreeAttachment(menutreeId);        response.reset();        response.setCharacterEncoding("utf-8");        response.setContentLength((int) file.length());// 设置content-disposition响应头控制浏览器以下载的形式打开文件，中文文件名要使用URLEncoder.encode方法进行编码，否则会出现文件名乱码        response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(file.getName(), "UTF-8"));        bis = new BufferedInputStream(new FileInputStream(file));        os = response.getOutputStream();byte[] buff = new byte[1024];int i = 0;while ((i = bis.read(buff)) != -1) {            os.write(buff, 0, i);            os.flush();        }    } catch (Exception e) {log.error("{}",e);return ResultGenerator.genFailResult("下载失败");    } finally {try {            bis.close();            os.close();        } catch (IOException e) {            e.printStackTrace();        }    }return ResultGenerator.genSuccessResult();}
感谢各位的阅读，以上就是"FTP服务器打包下载文件的步骤"的内容了，经过本文的学习后，相信大家对FTP服务器打包下载文件的步骤这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是，小编将为大家推送更多相关知识点的文章，欢迎关注！