input file multiple 配合springmvc实现多文件上传

1、前端页面的样子

<input id="file" name="file" type="file" multiple="multiple"  />
2、前端的js代码

var formData = new FormData(); 
            var files = $("#file")[0].files;
            for(var i = 0 ; i < files.length ; i ++){
                formData.append('file',files[i]);
            }
3、ajax的代码
$.ajax({
                   url: '${cpath}/biz/xxxx/addFile',
                    type: 'POST',
                    cache: false,
                    data: formData,
                    processData: false,
                    contentType: false
            }).done(function(res) {
                debugger;
            }); 
4、后端的代码

@RequestMapping(value = "addFile", method = RequestMethod.POST, produces = "application/json; charset=UTF-8")
    @ResponseBody
    public String addFile(HttpServletRequest request,HttpServletResponse response) {
        
        String rRoles = request.getParameter("rRoles");
        List<MultipartFile> fileList = new ArrayList<>();
        //创建一个通用的多部分解析器 
        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver(request.getSession().getServletContext());
        //判断 request 是否有文件上传,即多部分请求  
        if(multipartResolver.isMultipart(request)){
            //转换成多部分request    
            MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest)request;  
            //取得request中的所有文件名  
            fileList = multiRequest.getFiles("file");
            if (fileList == null || fileList.size() <= 0) {
                throw new Exception("上传文件失败");
            }
            System.out.println("");
        }
        return null;
    }
5、xml配置文件配置
    <bean id="multipartResolver"  
        class="org.springframework.web.multipart.commons.CommonsMultipartResolver">  
        <!-- set the max upload size100MB -->  
        <property name="maxUploadSize">  
            <value>104857600</value>  
        </property>  
        <property name="maxInMemorySize">  
            <value>4096</value>  
        </property>  
    </bean>