附件下载（包含打包压缩下载）

• 打包下载

/**
     * 将附件打包下载
     * @param list
     * @param zipName
     * @param session
     * @param response
     * @throws IOException
     */
    public void zipDownload(List<TCommonAtta> list, String zipName, HttpSession session, HttpServletResponse response)
            throws IOException {
        
        if(list.isEmpty()){
            return;
        }
        if(!zipName.contains(".zip")){
            zipName += ".zip";
        }

        int len;
        int countIndex = 0;
        byte[] buf = new byte[1024];
        List<String> li = new ArrayList<String>();
        File zipFile = new File(session.getServletContext().getRealPath("/") + "/myzip.zip");
        ZipOutputStream zout = new ZipOutputStream(new FileOutputStream(zipFile));
        
        for (TCommonAtta atta : list) {
            // 附件名称重复，则修改附件名称
            String attaName = atta.getAttaName();
            if (li.contains(attaName)) {
                attaName += String.valueOf(countIndex);
                countIndex++;
            }
            li.add(attaName);

            String attaPath = atta.getAttaPath();
            InputStream in = FastDFSFileUtils.downloadFile(attaPath);
            zout.putNextEntry(new ZipEntry(attaName + "." + atta.getAttaSuffix()));
            while ((len = in.read(buf)) > 0) {
                zout.write(buf, 0, len);
            }
            zout.closeEntry();
            in.close();
        }
        
        zout.close();
        zipName = new String(zipName.getBytes(), "ISO-8859-1");
        FileInputStream zipInput = new FileInputStream(zipFile);
        OutputStream out = response.getOutputStream();
        response.setContentType("application/octet-stream");
        response.setHeader("Content-Disposition", "attachment; filename=" + zipName);
        
        while ((len = zipInput.read(buf)) != -1) {
            out.write(buf, 0, len);
        }
        zipInput.close();
        out.flush();
        out.close();
        // 删除压缩包
        zipFile.delete();
    }

• 普通下载

public void download (String attaPath, String filename, HttpServletRequest request, HttpServletResponse response)
            throws IOException{
        InputStream ips = null;
        response.reset();
        response.setContentType("application/x-msdownload");
        response.setHeader("Content-Type", "application/octet-stream");
        ServletOutputStream out = response.getOutputStream();
        // 获得浏览器信息并转换为大写
        String agent = request.getHeader("User-Agent").toUpperCase();
        try {
            if (agent.indexOf("MSIE") > 0 || (agent.indexOf("GECKO") > 0 && agent.indexOf("RV:11") > 0)) { // IE浏览器和Edge浏览器
                filename = URLEncoder.encode(filename, "UTF-8");
            } else { // 其他浏览器
                filename = new String(filename.getBytes("UTF-8"), "iso-8859-1");
            }
            response.setHeader("content-disposition", "attachment;filename=" + filename);
            ips = FastDFSFileUtils.downloadFile(attaPath);
            int len = 0;
            byte[] buffer = new byte[1024 * 10];
            while ((len = ips.read(buffer)) != -1) {
                out.write(buffer, 0, len);
            }
            out.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            out.close();
            ips.close();
        }
    }