@ApiOperation(value="圖片下載",notes="")
	@RequestMapping(value="downPhoto",method=RequestMethod.GET)
	public void downPhoto(
			@RequestParam(value = "tid") Long tid,
			HttpServletRequest request,
			HttpServletResponse response
		) throws BusinessException{
		Photo photo = photoService.findPhoto(tid).getObject();
		photoService.updatePhotoDownNum(tid);
		String url = fileUploadPath+photo.getUrl();
		String ext = url.substring(url.lastIndexOf("."));
		//獲取檔名
		Long filename = new Date().getTime();
		//設定響應頭和下載儲存的檔名 
		response.setContentType("APPLICATION/OCTET-STREAM"); 
		//如果圖片名稱是中文需要設定轉碼
		//response.setHeader("content-disposition", "attachment;fileName="+URLEncoder.encode(fileName, "UTF-8"));
		response.setHeader("Content-Disposition", "attachment;  filename=\""  +  filename+ext  +  "\"");
		try {
		//開啟指定檔案的流資訊 
		OutputStream outputStream = response.getOutputStream();
		InputStream inputStream = new FileInputStream(url);
		byte[] buffer = new byte[1024];
		int i = -1;
		while ((i = inputStream.read(buffer)) != -1) {
		  outputStream.write(buffer, 0, i);
		}
		outputStream.flush();
		outputStream.close();
		
		inputStream.close();

		} catch (IOException e) {
			e.printStackTrace();
		}
	}
 

// js 程式碼

$("[name='downloadButton']").on("click",function(){
			var tid = $(this).attr("tid");
			var empId = $(this).attr("empId");
			if(userId == '' || !userId){
				alert("請先登入!");
				window.location = basePath;
			}
	
			var url = basePath+"/m/photo/downPhoto?tid="+tid;
			//console.log(url);
                       //這裡 是先建立 <a>標籤，在a標籤裡面需要有一個 便籤，裡面的標籤相對隨意，比如：span標籤，
                       //因為如果 只有 a 會用瀏覽器開啟 圖片
                       //注意我們 點選事件 是在 內部的標籤觸發的，通過事件冒泡傳遞給了 a，這樣就可以直接 下載檔案了
			var aa = $("<a href="+url+" id='forDownPhoto' ><p></p></a>");
			$(this).parent().append(aa);
			aa.find("p").trigger("click");//觸發內部的標籤點選事件
			aa.remove();//移除a標籤		
		})