java web ftp 打包下载文件

约定不等于承诺〃 2022-03-31 06:46 365阅读 0赞

## java web ftp 打包下载文件 ##

import org.apache.commons.io.FileUtils;
    import java.io.BufferedInputStream;
    import java.io.BufferedOutputStream;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    import java.util.UUID;
    import java.util.zip.ZipEntry;
    import java.util.zip.ZipOutputStream;
    
     /** * 多文件下载 * @param fileSns 文件sn * @param fileName 文件名称sn * @param response 响应 * @return 视图 */
        @RequestMapping(value = "/download-files", method = RequestMethod.GET)
        public void downloadFiles(@RequestParam List<Long> fileSns, String fileName, HttpServletRequest request, HttpServletResponse response) { 
            if (fileSns == null || fileSns.isEmpty()) { 
                throw new RuntimeException("文件为空");
            }
            //获取ftp存储的文件信息
            List<File> files = fileService.findListBySn(fileSns);
            if (files.isEmpty()) { 
                throw new RuntimeException("没有找到文件");
            }
            //临时文件
            java.io.File tempFile;
            //Zip工具
            ZipOutputStream out = null;
            //获取临时文件目录
            java.io.File fileDirecotry = FileUtils.getTempDirectory();
            if (StringUtils.isNotBlank(fileName)) { 
                //前端传过来的文件名要经过Base64加密，主要解决IE浏览器URL包含中文字符而无法正确请求地址
                //中文Base64加密可以参考下面里链接：
                //https://blog.csdn.net/Michean/article/details/86299631
                //https://blog.csdn.net/Michean/article/details/86294679
            	fileName = new String(Base64Utils.decode(fileName));
                fileName += "-" + System.currentTimeMillis();
            } else { 
                fileName = UUID.randomUUID().toString();
            }
            try { 
                //创建临时zip文件
                tempFile = java.io.File.createTempFile(fileName, ".zip", fileDirecotry);
                out = new ZipOutputStream(new FileOutputStream(tempFile));
                List<String> names = new ArrayList<>();
                //将多个文件写入zip
                for (File file : files) { 
                    //文件名去重
                    String name = distinctName(names, file.getOriginal());
                    //往zip文件流中写文件
                    out.putNextEntry(new ZipEntry(name));
                    //省去ftp链接
                    ftpClient.retrieveFile(file.getPath(), out)
                    out.flush();
                    out.closeEntry();
                }
                //所有文件写完后一定要关闭输出流，否则文件下载会不完整。
                out.flush();
                out.close();
    
                //将zip文件写入响应
                String name;
                String userAgent = request.getHeader("user-agent").toLowerCase();
                if (userAgent.contains("msie") || userAgent.contains("like gecko")) { 
                    // IE 中文编码
                    name = URLEncoder.encode(tempFile.getName(), "UTF-8");
                } else { 
                    // 非IE 中文编码
                    name = new String(tempFile.getName().getBytes("UTF-8"), "ISO-8859-1");
                }
                response.setHeader("Content-Disposition", "attachment; filename=" + name);
                OutputStream os = new BufferedOutputStream(response.getOutputStream());
                InputStream in = new BufferedInputStream(new FileInputStream(tempFile));
                int len;
                byte[] buf = new byte[1024];
                while ((len = in.read(buf)) > 0) { 
                    os.write(buf, 0, len);
                }
                os.flush();
                os.close();
                in.close();
                response.flushBuffer();
                FileUtils.deleteQuietly(tempFile);
            } catch (Exception e) { 
                e.printStackTrace();
                if (out != null) { 
                    try { 
                        out.close();
                    } catch (IOException ie) { 
                        ie.printStackTrace();
                    }
                }
                throw new RuntimeException();
            }
        }
        /** * 文件名去重 * @param names 名称集合 * @param name 文件名 * @return 去重文件名 */
        private String distinctName(List<String> names, String name) { 
            if (!names.contains(name)) { 
                names.add(name);
                return name;
            }
            int count = 0;
            int pos = name.lastIndexOf(StringUtils.DOT);
            String namePrev = name;
            String nameEnd = "";
            if (pos > 0) { 
                namePrev = name.substring(0, pos);
                nameEnd = name.substring(pos);
            }
            String tmpName;
            do { 
                count++;
                tmpName = namePrev + StringUtils.LEFT_BRACKET + count + StringUtils.RIGHT_BRACKET + nameEnd;
            } while (names.contains(tmpName));
            names.add(tmpName);
            return tmpName;
        }