前台将查询条件传入后台，查询数据库，选择保存路径，然后导出excel

JS代码

exportExcel = function (type) {
	var obj=JSON.stringify($('#searchForm').serializeJSON());
	$.ajax({
        //这里是公共方法的连接
        url: "exportExcelController/submitExcelData.action",
        type: "post",
        dataType: "json",
        data:"obj="+obj,
        success: function (data) {
            if (data&&data.code=="1") {
                 //这里是每个JavaBean对应的控制层方法
                 window.location.href = "dogController/export.action";
                //我们这里缺少导出成功的提示，有需要的自行想办法添加                         
            } else {
            	$.messager.show({
					title:'提示',
					msg:"导出失败~",
					timeout:3000,
					showType:'slide'
				});
            }
        },
        error: function (err) {
        	$.messager.show({
				title:'提示',
				msg:"导出失败~",
				timeout:3000,
				showType:'slide'
			});
        }
    });                
	 
	
};

controller层java代码

	@RequestMapping(value = "submitExcelData")
	@ResponseBody
	public String submitExcelData(HttpServletRequest request, HttpServletResponse response, String obj) throws IOException {
		// 设置响应和请求编码utf-8
		request.setCharacterEncoding("UTF-8");
        JSONObject jsonResult = new JSONObject(); // 返回界面端的json对象

		// 将参数信息存入session中
		HttpSession session = request.getSession();
        //这里可以先做非空判断，不写了
		try {
			session.setAttribute("obj", obj);
		} catch (Exception e) {
            jsonResult.put("code","0");
			return jsonResult.toString();
		}
        jsonResult.put("code","1");
		return jsonResult.toString();
	}

    

@RequestMapping("export")
	@ResponseBody
	public String exportExcel(HttpServletRequest request, HttpServletResponse response) throws IOException {
		HttpSession session = request.getSession();
		String obj=(String)session.getAttribute("obj");
		
		//如果页面传的是json字符串，用下列方式解析
		JSONObject parseObject = JSONObject.parseObject(obj); //string转json
        //将json数据转换为Dog对象，作为我们的查询条件
		Dog dog= (Dog ) JSONObject.toJavaObject(parseObject, Dog .class);
		
		List<Dog > list = dogService.findJksbxxb(dog);//从数据库查询需要的数据
		String result = "";
        
        //这里是个公共方法
		result = ExportExcelTool.downloadExcel(request, response, list);
		return result;
	}

公共方法

public static String downloadExcel(HttpServletRequest request, HttpServletResponse response,List list) throws IOException {
		// 设置响应和请求编码utf-8
		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		String result = "导出失败";
		HttpSession session = request.getSession();

		Date date = new Date();
		DateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
		String strFileName = format.format(date) + ".xls";// 默认当前时间为Excel名称
		response=setResponseHeader(request, response, strFileName);//设置表头
		response.flushBuffer();// 刷新缓冲
		result = exportToExcel(list, response);
		return result;
	}

	/**
	 * 设置response表头，这个关键
	 * @param request
	 * @param response
	 * @param strFileName
	 * @return
	 * @throws UnsupportedEncodingException
	 */
	public static HttpServletResponse setResponseHeader(HttpServletRequest request,HttpServletResponse response,
			String strFileName) throws UnsupportedEncodingException{
		response.setContentType("application/octet-stream; charset=utf-8");
		if (request.getHeader("User-Agent").toLowerCase().indexOf("firefox") > 0) {
			response.setHeader("Content-Disposition",
					"attachment; filename=" + new String(strFileName.getBytes("UTF-8"), "ISO8859-1"));// firefox浏览器
		} else if (request.getHeader("User-Agent").toUpperCase().indexOf("MSIE") > 0) {
			response.setHeader("Content-Disposition",
					"attachment; filename=" + URLEncoder.encode(strFileName, "UTF-8"));// IE浏览器
		} else {
			response.setHeader("Content-disposition", "attachment;filename=" + strFileName);
		}
		return response;
	}

/**
	 * 导出Excel
	 * @param dataList
	 * @param filePath
	 * @param req 
	 */
	public static String exportToExcel(List dataList,HttpServletResponse response){
		//导出结果
		String result = "";
		//创建Excel工作簿
		HSSFWorkbook workbook = new HSSFWorkbook();
		//创建一个工作表sheet
		HSSFSheet sheet = workbook.createSheet();
		//创建第一行
		HSSFRow row = sheet.createRow(0);
		HSSFCell cell = null;
		//插入第一行数据，中文列名
        /*自行添加*/		

		//追加数据  dataList.size()行数
		for (int i = 0; i < dataList.size(); i++) {
			HSSFRow nextrow = sheet.createRow(i+1);
			//向每一列填充数据
			Object obj = dataList.get(i);
			/*自己添加*/
		}
		try {
            //最后一步，已流的形式返回
			workbook.write(response.getOutputStream());
			result = "导出成功";
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			result = "导出失败";
		}				
		return result;
	}

由于本人菜鸟一枚，理解比较肤浅，很难解释清楚原理，方法也都是从网上各个地方看来的，这里只是做个总结。

虽然解释不清楚，但是主体代码应该比较详尽，基本上根据各自项目需求稍作修改就可以用。

前台需要引入JQuery和jquery.serializeJSON。

jquery.serializeJSON的下载地址

https://github.com/marioizquierdo/jquery.serializeJSON

后台需要阿里巴巴的FastJSON