java如何直接返回excel到客户端

既然是web项目首先你得拿到响应才能向外部写出，你得拿到响应对象response，
1.添加如下两行代码
response.setContentType("application/vnd..ms-excel");
response.setHeader("content-Disposition","attachment;filename="+URLEncoder.encode(“abc.xlsx”,"utf-8"));
2.修改你的写出方式：

HSSFWorkbook hssfWorkbook = new HSSFWorkbook();

hssfWorkbook.write(response.getOutputStream());