/**
     * 下载文件
     * @param filePath 文件路径(物理路径)
     * @param fileName 源文件名称
     */
    public void downLoadFile(String filePath, String fileName) {
        File file = new File(filePath);
        if (!file.exists() || file.isDirectory()) {
            return;
        }
        InputStream input =null;
        OutputStream output = null;
        try {
            input = new FileInputStream(file);
            output = getResponse().getOutputStream();
            getResponse().setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
            byte[] buffer = new byte[1024];
            int i = 0;
            while ((i = input.read(buffer)) != -1) {
                output.write(buffer, 0, i);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if(null !=output) {
                    output.flush();
                    output.close();
                }
                if(null !=input) {
                    input.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }