• Java以压缩包方式下载文件


    从云服务器上下载文件,以压缩包方式下载

    • 以下载多个文件为例,需要导入zip4j的jar包,版本不要太高
    public void downloadZip(List<fielEntiry> list, HttpServletRequest request, HttpServletResponse response) {
                    String zipFileName = "";
                    File[] tempList = null;
    		//因为我这边在classpath下无法获取到新建文件夹,所以使用路径拼接
                    String path = this.getClass().getClassLoader().getResource("template/").getPath();
                    path += "tempPack";
                    File outFile = new File(path);
                    for (fielEntiry file : list) {
                        String url = file.getUrl();//云服务器文件链接
                        String fileName = assc.getFileName();
    
                        if (!outFile.exists()) {
                            outFile.mkdirs();
                        }
                        try {
                            download(url, path, fileName);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                    zipFileName = "/报告.zip";
                    tempList = outFile.listFiles();
                    createZipFile(path, zipFileName, tempList);
                    for (File file : outFile.listFiles()) {
                        download(file, request, response);
                    }
                } else {
                    throw new BadRequestException("暂无报告附件");
                }
            }
        }
    

    *下载文件到临时文件夹

       public void download(String urlPath, String targetDirectory, String fileName) throws Exception {
            URL url = new URL(urlPath);
            HttpURLConnection http = (HttpURLConnection) url.openConnection();
            InputStream inputStream = http.getInputStream();
            byte[] buff = new byte[1024 * 10];
            OutputStream out = new FileOutputStream(new File(targetDirectory, fileName));
            int lenth = -1;
            while ((lenth = inputStream.read(buff)) != -1) {
                out.write(buff, 0, len);
                out.flush();
            }
            // 关闭资源
            out.close();
            inputStream.close();
            http.disconnect();
        }
    

    *将文件打包成zip文件

        public static ZipFile createZipFile(String templatePathZip, String fileName, File... files) {
            try { // 创建zip包,指定路径和名称
                final ZipFile zipFile = new ZipFile(templatePathZip + fileName);
                // 向zip包中添加文件集合
                final ArrayList<File> fileAddZip = new ArrayList<File>();
                File file1 = zipFile.getFile();
                if (file1.exists()) {
                    file1.delete();
                }
    		// 向zip包中添加文件
                for (File file : files) {
                    fileAddZip.add(file);
                }
    		// 设置zip包的一些参数集合
                final ZipParameters parameters = new ZipParameters();
    		// 是否设置密码(若passwordZip为空,则为false)
                /*if (null != passwordZip && !passwordZip.equals("")) {
                    parameters.setEncryptFiles(true);
                    // 压缩包密码
                    parameters.setPassword(passwordZip);
                } else { }*/
                parameters.setEncryptFiles(false);
    
    		// 压缩方式(默认值)
                parameters.setCompressionMethod(Zip4jConstants.COMP_DEFLATE);
    		// 普通级别(参数很多)
                // parameters.setCompressionLevel(Zip4jConstants.DEFLATE_LEVEL_NORMAL);
    		// 加密级别
                // parameters.setEncryptionMethod(Zip4jConstants.ENC_METHOD_STANDARD);
    		// 创建压缩包完成
                zipFile.createZipFile(fileAddZip, parameters);
    		//压缩完成后删除文件
                for (File file : files) {
                    file.delete();
                }
                return zipFile;
            } catch (final Exception e) {
                e.printStackTrace();
                return null;
            }
        }
    

    *下载生成的word文件并删除临时文件

        private void download(File file, HttpServletRequest request, HttpServletResponse response) {
    
            ServletOutputStream out = null;
            FileInputStream inputStream = null;
            try {
                String filename = file.getName();
                String userAgent = request.getHeader("User-Agent");
                // 针对IE或者以IE为内核的浏览器:
                if (userAgent.contains("MSIE") || userAgent.contains("Trident")) {
                    filename = java.net.URLEncoder.encode(filename, "UTF-8");
                } else {
                    // 非IE浏览器的处理:
                    // filename = URLEncoder.encode(filename, "UTF-8");
                    filename = new String(filename.getBytes("UTF-8"), "ISO-8859-1");
                }
                response.setHeader("Content-disposition",
                        String.format("attachment; filename="%s"", filename));
                response.setContentType("application/download");
                response.setCharacterEncoding("UTF-8");
                out = response.getOutputStream();
                inputStream = new FileInputStream(file);
                byte[] buffer = new byte[1024 * 10];
                int lenth = -1;
                // 通过循环将读入的Word文件的内容输出到浏览器中
                while ((lenth = inputStream.read(buffer)) != -1) {
                    out.write(buffer, 0, bytesToRead);
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    if (null != out) out.close();
                    if (null != inputStream) inputStream.close();
                    file.delete();
                } catch (Exception e2) {
                    e2.printStackTrace();
                }
            }
        }
    

    注:部分代码是在网上查找的资料,然后根据自己需要写的

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  • 原文地址:https://www.cnblogs.com/mengzhao/p/13744541.html
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