//第一步创建一个webbook,对应一个Excel文件
	HSSFWorkbook wb=new HSSFWorkbook();
	//第二步,在webbook中添加一个sheet,对应Excel文件中的sheet
	HSSFSheet sheet=wb.createSheet("食物信息数据");
	//第三步，在sheet中添加表头第0行
	HSSFRow row = sheet.createRow(0);
	//第四步，创建单元格，并设置表头居中
	HSSFCellStyle style = wb.createCellStyle();
	style.setAlignment(HorizontalAlignment.CENTER);//居中格式
	HSSFCell cell = row.createCell(0);
	cell.setCellValue("编号");
	cell.setCellStyle(style);
	
	cell=row.createCell((short)1);
	cell.setCellValue("名称");
	cell.setCellStyle(style);
	
	cell=row.createCell((short)2);
	cell.setCellValue("类型");
	cell.setCellStyle(style);
	
	cell=row.createCell((short)3);
	cell.setCellValue("单价");
	cell.setCellStyle(style);
	
	cell=row.createCell((short)4);
	cell.setCellValue("库存");
	cell.setCellStyle(style);
	
	//第五步，写入实体数据，从数据库拿数据
	FoodController controller=new FoodController();
	List<Foods> foodsList = controller.foodsList(null, null);
	for (int i = 0; i < foodsList.size(); i++) {
		//创建单元格，并赋值
		row=sheet.createRow(i+1);
		Foods foods = foodsList.get(i);
		row.createCell((short)0).setCellValue(foods.getId());
		row.createCell((short)1).setCellValue(foods.getName());
		row.createCell((short)2).setCellValue(foods.getType());
		row.createCell((short)3).setCellValue(foods.getPrice());
		row.createCell((short)4).setCellValue(foods.getNum());
	}
	//第六步，下载Excel
	OutputStream out=null;
	out=response.getOutputStream();
	String fileName="食物信息.xls";
	response.setContentType("application/x-=msdownload");
	response.setHeader("Content-Disposition", "attachment; filename="
			+URLEncoder.encode(fileName, "UTF-8"));
	wb.write(out);