java - 下载或预览文件

封装了个方法，根据需要可以改造成异常抛出

  /**
     * 下载、预览文件【导出文件】
     */
    public static boolean expFile(HttpServletResponse response, String fileName, File file, boolean isDel, boolean isPre) {
        InputStream fis = null;
        try {
            fis = new BufferedInputStream(new FileInputStream(file));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            fis.close();
            response.reset();
            response.addHeader("Content-Length", String.valueOf(file.length()));
            response.setHeader("Access-Control-Allow-Origin", "*");
            response.setContentType("application/octet-stream; charset=utf-8");
            response.setCharacterEncoding("UTF-8");
            response.setHeader("Content-Disposition", (isPre ? "inline" : "attachment") + ";filename="
                    + URLEncoder.encode(fileName, "UTF-8"));
            OutputStream ops = new BufferedOutputStream(response.getOutputStream());
            ops.write(buffer);
            ops.flush();
            ops.close();
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        } finally {
            try {
                if (null != fis) fis.close();
                if (null != file && file.exists() && isDel) file.delete();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return true;
    }