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;
}