1 <form action="${pageContext.request.contextPath}/upload.do" enctype="multipart/form-data" method="post">2 ??上传文件1:<input type="file" name="file1"></br>3 ??上传文件2:<input type="file" name="file2"></br>4 ??上传文件3:<input type="file" name="file3"></br>5 ??<input type="submit" value="提交"/>${result}6 </form>

1 <servlet>2 ????????<servlet-name>UploadServlet</servlet-name>3 ????????<servlet-class>uploadServlet.UploadServlet2</servlet-class>4 ????</servlet>5 ????<servlet-mapping>6 ????????<servlet-name>UploadServlet</servlet-name>7 ????????<url-pattern>/upload.do</url-pattern>8 ????</servlet-mapping>

 1 public class UploadServlet2 extends HttpServlet { 2 ?3 ????@Override 4 ????protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 5 ????????//super.doGet(req, resp); 6 ????????doPost(req,resp); 7 ????} 8 ?9 ????@Override10 ????protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {11 ????????/**设置上传保存路径*/12 ????????String filePath = getServletContext().getRealPath("/")+"images";13 ????????File file = new File(filePath);14 ????????if (!file.exists()){15 ????????????file.mkdir();16 ????????}17 ????????SmartUpload smartUpload = new SmartUpload();18 ????????/**初始化对象*/19 ????????smartUpload.initialize(getServletConfig(),req,resp);20 ????????/**设置上传文件大小*/21 ????????smartUpload.setMaxFileSize(1024*1024*100);22 ????????/**设置所有文件的大小*/23 ????????smartUpload.setTotalMaxFileSize(1024*1024*1000);24 ????????/**设置允许上传文件的类型*/25 ????????smartUpload.setAllowedFilesList("txt,jpg,png,gif");26 ????????String result = "上传成功";27 ????????try {28 ????????????smartUpload.setDeniedFilesList("rar,jsp,js");29 ????????????smartUpload.upload();30 ????????????int count = smartUpload.save(filePath);31 ????????????System.out.println("上传成功了:"+count+"文件");32 ????????} catch (Exception e) {33 ????????????result = "上传失败";34 ????????????e.printStackTrace();35 ????????}36 　　　37 ????????req.setAttribute("result",result);38 ????????req.getRequestDispatcher("/index.jsp").forward(req,resp);39 40 ????}41 }

下载:<a href="${pageContext.request.contextPath}/download.do?filename=01.mp4">下载</a>

 1 /** 2 ?* @Author: jack 3 ?* @Create: 2018-08-29-16:25 4 ?* @Desc: 5 ?**/ 6 public class UploadServlet3 extends HttpServlet { 7 ?8 ????@Override 9 ????protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {10 // ???????super.doGet(req, resp);11 ????????doPost(req,resp);12 13 ????}14 15 ????@Override16 ????protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {17 ????????/**获取文件名*/18 ????????String filename = req.getParameter("filename");19 ????????/**初始化对象*/20 ????????SmartUpload su = new SmartUpload();21 ????????su.initialize(getServletConfig(),req,resp);22 ????????/**设定contentDisposition为null以禁止浏览器自动打开文件*/23 ????????su.setContentDisposition(null);24 ????????try {25 ????????????/**文件在服务器的地址*/26 ????????????su.downloadFile("/images/"+filename);27 ????????} catch (SmartUploadException e) {28 ????????????e.printStackTrace();29 ????????}30 ????}31 }

 1 <img id="img" src=""> 2 ????<button onclick="showImg()">显示</button> 3 ????<button onclick="coverImg()">隐藏</button><br/> 4 ?5 <script> 6 ????????/**显示图片*/ 7 ????????function showImg() { 8 ????????????var img = document.getElementById("img"); 9 ????????????????img.setAttribute("src","/image");10 11 ????????}12 ????????/**隐藏图片*/13 ????????function coverImg() {14 ????????????var img = document.getElementById("img");15 ????????????img.setAttribute("src","");16 ????????}17 </script> ???

 1 ** 2 ?????* 服务器向浏览器发送图片流 3 ?????* @param response 4 ?????* @throws IOException 5 ?????*/ 6 ????@RequestMapping("/image") 7 ????public void demo(HttpServletResponse response) throws IOException { 8 ????????/**设置编码格式*/ 9 ????????response.setContentType("charset=utf-8");10 ????????/**文件所在的位置*/11 ????????File file = new File("F:/temp/1.jpg");12 ????????FileInputStream in = new FileInputStream(file);13 ????????/**创建输出流向网页输入内容*/14 ????????OutputStream out = response.getOutputStream();15 ????????byte[] buffer = new byte[1024];16 ????????int len;17 ????????while ((len=in.read(buffer)) > 0){18 ????????????out.write(buffer,0,len);19 ????????}20 ????????/**关闭流*/21 ????????in.close();22 23 ????}