fileupload组件实现上传下载(下载不是组件的)

最新推荐文章于 2021-01-17 09:58:06 发布

原创最新推荐文章于 2021-01-17 09:58:06 发布 · 1.6k 阅读

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#string #file #servlet #buffer #exception #byte

java组件专栏收录该内容

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本文介绍了使用Java Servlet实现文件上传和下载的功能。通过Apache Commons FileUpload组件进行多文件上传处理，并展示了如何设置表单以支持文件上传。此外，还详细说明了文件下载过程中的乱码问题解决方案。

fileupload 下载地址

http://commons.apache.org/fileupload/

另外还需 io组件的支持

http://commons.apache.org/io/

上传选择的jsp页面

处理的servlet

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { request.setCharacterEncoding("UTF-8"); // 文件上傳部分 boolean isMultipart = ServletFileUpload.isMultipartContent(request); if (isMultipart == true) { try { FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); // 得到所有的表单域，它们目前都被当作FileItem List<FileItem> fileItems = upload.parseRequest(request); Iterator<FileItem> iter = fileItems.iterator(); // 依次处理每个表单域 while (iter.hasNext()) { FileItem item = (FileItem) iter.next(); if(item.isFormField()){ // 如果item是正常的表单域 String name = item.getFieldName(); String value = item.getString(); byte[] temp=value.getBytes("ISO-8859-1"); value=new String(temp,"UTF-8"); System.out.println(value); System.out.print("表单域名为:"+name+"表单域值为:"+value); } else{ // 如果item是文件上传表单域 // 获得文件名及路径 String fileName = item.getName(); if(!(new java.io.File(UploadUtil.getUploadPath()).isDirectory())){ new java.io.File(UploadUtil.getUploadPath()).mkdir(); //不存在 uploadfile 文件夹，则建立此文件夹 } //肇@ if (fileName != null) { File fullFile = new File(item.getName()); // 如果文件存在则上传 if(fullFile.exists()){ File fileOnServer = new File(UploadUtil.getUploadPath(), fullFile.getName()); item.write(fileOnServer); System.out.println("文件"+fileOnServer.getName()+"上传成功"); } } } } } catch (Exception e) { e.printStackTrace(); } } else { System.out.println("the enctype must be multipart/form-data"); } // 取得服务器中已有文件的下載列表 List<String> fileListInServer=new ArrayList<String>(); File dir = new File(UploadUtil.getUploadPath()); String[] children = dir.list(); if (children != null) { for (int i=0; i<children.length; i++) { fileListInServer.add(children[i]); } } request.setAttribute("downloadList", fileListInServer); // 跳回原頁面 RequestDispatcher dispatcher = request .getRequestDispatcher("/uploadtoserver.jsp"); dispatcher.forward(request, response); return; }

多文件上传jsp

<form name="uploadForm" method="post" action="UploadFile" enctype="multipart/form-data" > <p><input type="button" value="增加上传按钮" onclick="addUploadButton()"/></p> <p><input type="file" name="myfile1" value="浏览文件..." /></p> <p><input type="submit" value="上传"/></p> </form>

处理的servlet (上面的那个)

下载文件用的servlet

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { request.setCharacterEncoding("UTF-8"); //肇@ String filename=request.getParameter("file"); //byte[] temp=filename.getBytes("ISO-8859-1"); //filename=new String(temp,"UTF-8"); System.out.println(filename); // 要下載的文件名 //String filename=request.getParameter("file"); // 文件真实地址 String filePathname = UploadUtil.getUploadPath()+File.separator+filename; System.out.println(filePathname); //肇加 // 设置内容格式 response.setContentType("text/x-msdownload"); response.setCharacterEncoding("UTF-8"); //肇加 // 设置文件头信息 //response.setHeader("Content-Disposition","attachment; filename=" + filename + ""); //肇@ servlet下载出现乱码解决 response.setHeader("Content-disposition","attachment; filename="+new String(filename.getBytes("gb2312"),"iso8859-1")); OutputStream outputStream = response.getOutputStream(); InputStream inputStream = new FileInputStream(filePathname); 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(); outputStream = null; }

注意，下载时不出现乱码,关键就是setHeader里的filename需要重新编码,格式是ISO-8859-1就ＯＫ了