我认为您缺少getter和setter方法，我不知道您是否已定义？
JSP代码：
<form action="FileUploadServletAction" method="post" enctype="multipart/form-data"> <label>File:</label><input type="file" name="userKey"/> <input type="image" src="images/login-btn.jpg" alt="submit" width="103" height="42"/></form>
动作代码：
//In FileUploadServletActionprivate File userKey; //file name which is on JSPprivate String userKeyContentType;private String userKeyFileName;//getter, setter public File getUserKey() { return userKey;}public void setUserKey(File userKey) { this.userKey = userKey;}public String getUserKeyFileName(){ return userKeyFileName;}public String getUserKeyContentType() { return userKeyContentType;}public void setUserKeyContentType(String userKeyContentType){ this.userKeyContentType = userKeyContentType;}public void setUserKeyFileName(String userKeyFileName){ this.userKeyFileName = userKeyFileName;}现在，
execute()方法
//In FileUploadServletActionpublic String execute() throws Exception{ try { String filePath = request.getSession().getServletContext().getRealPath("/"); File fileToCreate = new File(filePath, this.userKeyFileName); FileUtils.copyFile(this.userKey, fileToCreate); } catch (Exception e) { e.printStackTrace(); addActionError(e.getMessage()); return INPUT; } return SUCCESS;}
