Springmvc异步上传文件

<script src="js/jquery.js" type="text/javascript"></script><script src="js/jquery.ext.js" type="text/javascript"></script><script src="js/jquery.form.js" type="text/javascript"></script><form action="" method="post" id="jvForm" enctype="multipart/form-data">
        <input type="text" name="name"/>
        <input type="file" name="pic" id="pic"/>
        <input type="submit" value="提交"/>
</form><script>      $(function(){          var options = {              url : "upload/uploadPic.do",              dataType : "json",              type : "post",              success : function(data){                  alert(2);              }          };          $("#pic").change(function(){              alert(1);             $("#jvForm").ajaxSubmit(options)          });      });</script

springmvc配置文件处理器：

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
     <property name="maxUploadSize" value="1048576"/>
</bean>

controller

@Controller
@RequestMapping(value = "/upload")
public class UploadController {
    
    @RequestMapping(value = "/uploadPic.do")
    public String uploadPic(@RequestParam(required=false) MultipartFile pic){
        System.out.println(pic.getOriginalFilename());
        return "success";
    }
    
}