原文地址：https://blog.csdn.net/niceliusir/article/details/78453560
以下是jsp+servlet和SSM分别是如何实现文件上传的方法示例
两种模式的upload.jsp文件都一样，（注意要加上enctype=”multipart/form-data”）如下：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="指定控制器" method="post" enctype="multipart/form-data"> <table> <tr> <td>用户名：</td> <td><input type="text" name="username"></td> </tr> <tr> <td>文件：</td> <td><input type="file" name="uploadfile"></td> </tr> <tr> <td></td> <td><input type="submit" name="upload" value="上传"></td> </tr> </table> </form> </body> </html>传统的jsp+servlet开发实现上传
UploadServlet.java中的doPost()如下：
/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;chartset=utf-8"); request.setCharacterEncoding("utf-8"); // 上传的用户名 String value = null; // 上传的文件名 String fileName = null; // 上传的目标路径 String filePath = request.getSession().getServletContext().getRealPath("/upload"); // 1.判断表单上传的编码方式 if(ServletFileUpload.isMultipartContent(request)){ // 2.创建fileItem工厂 FileItemFactory factory = new DiskFileItemFactory(); // 3.创建上传解析对象 ServletFileUpload sfu = new ServletFileUpload(factory); // 4.解析上传的表单 List<FileItem> fileItemList = null; try { fileItemList = sfu.parseRequest(request); } catch (FileUploadException e) { // TODO Auto-generated catch block e.printStackTrace(); } for(FileItem f : fileItemList){ if(f.isFormField()){// 普通表单元素 String name = f.getFieldName(); if(name.equals("username")){ value = f.getString("utf-8"); } }else{// 文件 fileName = f.getName(); File file = new File(filePath + "/" + fileName); try { f.write(file); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } response.getWriter().print(value + "上传了" + fileName + "已成功！"); } } } }SSM框架主要是spring MVC处理器对上传组件进行了封装，使得代码简化了很多
处理器中的处理上传文件的方法如下：
/** * 文件上传 *TODO *LIU * @param request * @param response * @return *上午10:34:15 */ @RequestMapping("uploadFile.action") public ModelAndView uploadFile(@RequestParam("uploadfile") CommonsMultipartFile cmf, HttpServletRequest request) throws Exception{ // 接收普通的用户名的话，用参数request来接收 String uname = request.getParameter("uname"); String path = "F:\\upload\\" + cmf.getOriginalFilename(); File file = new File(path); cmf.transferTo(file); mav = new ModelAndView("uploadResult.jsp"); String mess = cmf.getOriginalFilename() + "上传成功了！"; mav.addObject("mess", mess); mav.addObject("uname", uname); return mav; }