一.顯示下載的文件資源
要將Web應(yīng)用系統(tǒng)中的文件資源提供給用戶進(jìn)行下載，首先我們要有一個(gè)頁面列出上傳文件目錄下的所有文件，當(dāng)用戶點(diǎn)擊文件下載超鏈接時(shí)就進(jìn)行下載操作，編寫一個(gè)ListFileServlet，用于列出Web應(yīng)用系統(tǒng)中所有下載文件。
1.1 文件下載頁面
download.html代碼如下:
<!DOCTYPE HTML><html><head> <title>下載文件顯示頁面</title></head><body> <div id="fileName"></div></body><script >$(function(){ download();}); function download(){ $.ajax({ url: 'cloud/load/download', type: 'POST', dataType:'JSON', cache: false, processData: false, contentType: false, success : function(date){ var file=""; $.each(date,function(key,values){ var newKey = "/D:/Download/"+key; file += "<div>"+key+" "+"<a href='cloud/load/downloadFile?fileName="+key+"'>"+"下載"+"</a>"+"</div>"+"<br>"; $(values).each(function(){ file+="/t"+this; }); }); alert("success"); }, error : function(e){ alert("error"); } }); }</script></html>1.2 controller
@RequestMapping(value = "/download", method = RequestMethod.POST)@ResponseBody public Map<String,String> download(HttpServletRequest request, HttpServletResponse response, ModelMap model) throws ServletException, IOException{ Map<String,String> map = fileLoadService.doGet(request, response); return map;}1.3 service
/** * 文件下載顯示 * @ClassName: FileLoadServiceImpl * @throws IOException * @throws ServletException */ @Overridepublic Map<String,String> doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ //獲取上傳文件的目錄 String uploadFilePath = "/D:/Download/"; //存儲(chǔ)要下載的文件名 Map<String,String> fileNameMap = new HashMap<String,String>(); //遞歸遍歷filepath目錄下的所有文件和目錄，將文件的文件名存儲(chǔ)到map集合中 listfile(new File(uploadFilePath),fileNameMap); return fileNameMap; } public void listfile(File file,Map<String,String> map){ //如果file代表的不是一個(gè)文件，而是一個(gè)目錄 if(!file.isFile()){ //列出該目錄下的所有文件和目錄 File files[] = file.listFiles(); //遍歷files[]數(shù)組 for(File f : files){ //遞歸 listfile(f,map); } }else{ String realName = file.getName().substring(file.getName().indexOf("_")+1); //file.getName()得到的是文件的原始名稱，這個(gè)名稱是唯一的，因此可以作為key，realName是處理過后的名稱，有可能會(huì)重復(fù) map.put(file.getName(), realName); }}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response);}二.下載顯示的文件資源
2.1 controller
@RequestMapping(value = "/downloadFile", method = RequestMethod.GET)@ResponseBodypublic void downloadFile(HttpServletRequest request, HttpServletResponse response, ModelMap model) throws ServletException, IOException{ String filename =request.getParameter("fileName"); fileLoadService.doGetFile(request, response ,filename); }2.2 service
/** * 下載文件到本地 start */ @Override public void doGetFile(HttpServletRequest request, HttpServletResponse response,String filename) throws ServletException,IOException { //得到要下載的文件名 String fileName = filename; fileName = new String(fileName.getBytes("iso8859-1"),"UTF-8"); String fileSaveRootPath="/D:/Download"; File file = new File(fileSaveRootPath + "/" + fileName); //如果文件不存在 if(!file.exists()){ request.setAttribute("message", "您要下載的資源已被刪除！！"); return; } //處理文件名 String realname = fileName.substring(fileName.indexOf("_")+1); //設(shè)置響應(yīng)頭，控制瀏覽器下載該文件 response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(realname, "UTF-8")); InputStream fis = new BufferedInputStream(new FileInputStream(fileSaveRootPath + "http://" + fileName)); byte[] buffer = new byte[fis.available()]; fis.read(buffer); //讀取文件流 fis.close(); response.reset(); //重置結(jié)果集 response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(realname, "UTF-8")); response.addHeader("Content-Length", "" + file.length()); //返回頭 文件大小 response.setContentType("application/octet-stream"); //設(shè)置數(shù)據(jù)種類 OutputStream os = new BufferedOutputStream(response.getOutputStream()); os.write(buffer); // 輸出文件 os.flush(); os.close(); }public void doPostFile(HttpServletRequest request, HttpServletResponse response,String filename)throws ServletException, IOException { doGetFile(request, response,filename);}以上文件下載完成。
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