E1. Weights Division (easy version) 解析(思維、優先佇列、樹狀DP)
阿新 • • 發佈：2020-11-22
<body> <form action="/UploadServlet" method="post" enctype="multipart/form-data"> 使用者名稱：<input name="uname"/> <br/> 頭像： <input type="file" name="upicture"/> <br/> <input type="submit" value="提交"/> </form> <a href="DownloadServlet?filename=1.png">檔案下載</a> </body> @WebServlet("/UploadServlet") public class UploadServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //獲取檔案上傳的路徑--伺服器路徑 String realPath = request.getServletContext().getRealPath("/image/user"); File f = new File(realPath); if(!f.exists()) { f.mkdirs(); } //設定編碼 request.setCharacterEncoding("utf-8"); response.setContentType("text/html; charset=UTF-8"); response.setCharacterEncoding("utf-8"); try { //判斷前臺的form是否是要上傳檔案 boolean isMultipart = ServletFileUpload.isMultipartContent(request); if (isMultipart) { DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); upload.setSizeMax(1024*200);//200kB //form中的所有請求欄位將儲存到 items集合中 包括使用者名稱和頭像，不能再用request.getParameter方法 List<FileItem> items = upload.parseRequest(request); //遍歷集合，分別處理簡單資料和檔案資料 Iterator<FileItem> iter = items.iterator(); while (iter.hasNext()) { FileItem item = iter.next(); //String itemName = item.getFieldName(); if (item.isFormField()) {//普通欄位--使用者名稱 String name = item.getString("UTF-8"); }else {//檔案 String fileName = item.getName(); //判斷是否為圖片 String ext = fileName.substring( fileName.indexOf(".")+1 ) ; if(!(ext.equals("png") || ext.equals("gif") ||ext.equals("jpg"))) { System.out.println("圖片型別有誤！格式只能是 png gif jpg"); return ;//終止 } //處理圖片 String newFileName = UUID.randomUUID().toString() + fileName.substring(fileName.lastIndexOf("."), fileName.length()); String path=realPath+File.separator+newFileName; File file = new File(path); item.write(file);// 上傳 System.out.println(fileName + "上傳成功！"); return; } } } } catch (FileUploadException e) { // TODO Auto-generated catch block e.printStackTrace(); }catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } }