List<MultipartFile>序列化成String和将序列化成String的文件反序列化

public String uploadFj(List<MultipartFile> files){
        try {
            
            if(files==null||files.size()==0){
                throw new RuntimeException("附件为空");
            }
            List<Map<String,Object>>list =new ArrayList<Map<String,Object>>();
            for(MultipartFile f:files){
                Map<String,Object>map=new HashMap<String,Object>();
                String filename = f.getOriginalFilename();
                byte[] bytes = f.getBytes();
                map.put("fileName", filename);
                map.put("fileByte", Base64.encodeBase64String(bytes));
                list.add(list.size(),map);
            }
            String jsonfiles = JSONObject.toJSONString(list);
            
            return jsonfiles;
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage());
        }
    }

public void formatUpload01(String fid, String userid, String username, String businesstag, String fileobj){
         try {
            List<Map> attachList=JSONObject.parseArray(fileobj,Map.class);
            if(attachList!=null && attachList.size()>0){
                String fileid = null;
                for(Map m:attachList){
                    byte[] fileByte=Base64.decodeBase64(m.get("fileByte")==null?"":m.get("fileByte").toString());
                    String fileName=m.get("fileName").toString();
                }
            }
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage());
        }
     }