java页面导出excel，csv文件

//platform 为前端传入的，用于判断不同操作系统下的换行符

protected String getNewLine(String platform) {
    if (StringUtils.equals(platform, "MacIntel")) {
        return "\n";
    } else if (StringUtils.equals(platform, "Macintosh") || StringUtils.equals(platform, "Mac68K")) {
        return "\r";
    } else if (StringUtils.startsWith(platform, "Linux")) {
        return "\n";
    } else if (StringUtils.equals(platform, "Windows") ||
            StringUtils.equals(platform, "Win16") ||
            StringUtils.equals(platform, "Win32") ||
            StringUtils.equals(platform, "WinCE")) {
        return "\r\n";
    }

    throw new NoteException("无法确定该系统使用的换行符.");
}

@RequestMapping(value = "/export", method = RequestMethod.GET)
public void export(HttpServletResponse response, String platform, String startTime, String endTime, String title) {

    String newLine = getNewLine(platform);

    long now = System.currentTimeMillis();
    if (null != startTime) {
        if (Long.parseLong(startTime) > now) {
            throw new NoteException("筛选的开始时间不可超过当前时间.");
        }
    }

    List list = courseMapper.totalList(startTime, endTime, title, null, null);
    if (null == list || list.isEmpty()) {
        throw new NoteException("导出的数据为空.");
    }

    StringBuilder elems = new StringBuilder();

    //excel 头部信息
    elems.append("日期").append(",")
            .append("收益金额").append(",")
            .append("购买笔数").append(",")
            .append("购买人数").append(",")
            .append(newLine);

    //excel 内容
    for (LaitoonOrderView e : list) {
        elems.append(e.getTimeDisplay()).append(",")
                .append(e.getNeedPay()).append(",")
                .append(e.getBuyNum()).append(",")
                .append(e.getBuyPeople()).append(",")
                .append(newLine);
    }

    //方法一
   byte[] bytes;

   if (null != isOffice && isOffice) {
       //导出文件以wps的方式打开
       bytes = elems.toString().getBytes(StandardCharsets.UTF_8);
   } else {
       //导出文件以Microsoft excel的方式打开
       bytes = elems.toString().getBytes(Charset.forName("GB2312"));
  }

    // gc
    list = null;
    elems = null;

    OutputStream out = null;
    try {
        response.reset();
        response.addHeader("Content-Disposition", "attachment;filename=export-" + System.currentTimeMillis() + ".csv");
        response.setContentType("application/octet-stream");

        // 处理文件 返回流
        out = response.getOutputStream();

        //方法二
        //让response 告诉Excel，此CSV文件的编码为UTF-8

    //    out.write(new byte[]{(byte) 0xEF, (byte) 0xBB, (byte) 0xBF});


        out.write(bytes);
        out.flush();

    } catch (Exception e) {
        throw new NoteException(e);
    } finally {
        try {
            if (out != null) {
                out.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}