Servlet package and download multiple files

When a user downloads multiple files at a time, a download dialog box is usually displayed for each file to be downloaded, which causes great inconvenience to the user.

Ideally, after you select multiple files, the backend of the server directly packs them as zip files. The following is the implementation code.

Front-end Javascript code (create a form using Javascript and access the backend MultiDownload by submitting a form ):

Var tmpForm = document. createElement ("form"); tmpForm. id = "form1"; tmpForm. name = "form1"; document. body. appendChild (tmpForm); var tmpInput = document. createElement ("input"); // you can specify the tmpInput parameter. type = "text"; tmpInput. name = "fileUrls"; tmpInput. value = downloadUrls; // Insert the input box to tmpform. appendChild (tmpInput); tmpForm. action = "servlet/MultiDownload"; tmpForm. method = "get"; tmpForm. submit ();

// Remove the formdocument. body. removeChild (tmpForm) from html );

Back-end MultiDownload code:

Public class MultiDownload extends HttpServlet {private static final long serialVersionUID = 1L;/*** @ see HttpServlet # HttpServlet () */public MultiDownload () {super (); // TODO Auto-generated constructor stub}/*** @ see HttpServlet # doGet (HttpServletRequest request, HttpServletResponse * response) */protected void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubString strArray = null; strArray = request. getParameter ("fileUrls"); // when passed to servlet, the encoding is converted to a ISO-8859-1 by default and transcoded to GBKstrArray = new String (strArray. getBytes ("ISO-8859-1"), "GBK"); String [] filePathArray = strArray. split (","); String zipFileName = "product.zip"; response. setContentType ("application/x-msdownload"); // notify the customer of the MIME type of the file: response. setHeader ("Content-dis Position "," attachment; filename = "+ zipFileName); // The file directory to be downloaded ZipOutputStream zos = new ZipOutputStream (response. getOutputStream (); for (String filePath: filePathArray) {File file = new File (filePath); doZip (file, zos);} zos. close ();} /*** package as a zip file * @ param File the file to be packaged * @ param zos zip output stream * @ throws IOException */private void doZip (file File, ZipOutputStream zos) throws IOException {if (file. exist S () {if (file. isFile () {// if it is a file, write it to zos in the zip stream. putNextEntry (new ZipEntry (file. getName (); FileInputStream FCM = new FileInputStream (file); byte [] buffer = new byte [1024]; int r = 0; while (r = FCM. read (buffer ))! =-1) {zos. write (buffer, 0, r);} zos. flush (); FCM. close () ;}else {// if it is a directory. Recursively search for the file String dirName = file. getName () + "/"; zos. putNextEntry (new ZipEntry (dirName); File [] subs = file. listFiles (); for (File f: subs) {makeZip (f, dirName, zos) ;}}/ *** @ see HttpServlet # doPost (HttpServletRequest request, httpServletResponse * response) */protected void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stub }}

Servlet package and download multiple files