1.form的enctype=”multipart/form-data” 这个是上传文件必须的2.applicationContext.xml中 
    
      import java.io.File;  import java.util.Date;    import javax.servlet.http.HttpServletRequest;    import org.springframework.stereotype.Controller;  import org.springframework.ui.ModelMap;  import org.springframework.web.bind.annotation.RequestMapping;  import org.springframework.web.bind.annotation.RequestParam;  import org.springframework.web.multipart.MultipartFile;    @Controller  public class UploadAction {        @RequestMapping(value = "/upload.do")      public String upload(@RequestParam(value = "file", required = false) MultipartFile file, HttpServletRequest request, ModelMap model) {            System.out.println("开始");          String path = request.getSession().getServletContext().getRealPath("upload");          String fileName = file.getOriginalFilename();  //        String fileName = new Date().getTime()+".jpg";          System.out.println(path);          File targetFile = new File(path, fileName);          if(!targetFile.exists()){              targetFile.mkdirs();          }            //保存          try {              file.transferTo(targetFile);          } catch (Exception e) {              e.printStackTrace();          }          model.addAttribute("fileUrl", request.getContextPath()+"/upload/"+fileName);            return "result";      }    }