poi 文件导出

public void download(ByteArrayOutputStream byteArrayOutputStream, HttpServletResponse response, String returnName) throws IOException{
	//设置响应文件类型  MINI   可以在tomcat下的cof/web.xml 可以查到
		response.setContentType("application/octet-stream;charset=utf-8");
			//保存的文件名,必须和页面编码一致,否则乱码
		returnName = response.encodeURL(new String(returnName.getBytes(),"iso8859-1"));		
		response.addHeader("Content-Disposition",   "attachment;filename=" + returnName);  
		response.setContentLength(byteArrayOutputStream.size());
		
		ServletOutputStream outputstream = response.getOutputStream();	//取得输出流
		byteArrayOutputStream.writeTo(outputstream);					//写到输出流
		byteArrayOutputStream.close();									//关闭
		outputstream.flush();											//刷数据
	}