vant的Uploader 文件上传,图片数据回显问题

      <van-field name="photo" label="证件照" colon class="tx">
        <template #input>
          <van-image :src="staffPhoto ?staffPhoto : require('@/assets/icon/tx.png')" />
        </template>
      </van-field>
      <van-uploader :before-read="beforeRead" :after-read="afterRead">
        <van-button icon="add-o">上传证件照</van-button>
      </van-uploader>

    const afterRead = (file) => {
      state.staffPhoto = file.content;
    };

    // 返回布尔值
    const beforeRead = (file) => {
      if (file.type !== "image/jpeg") {
        Toast("请上传 jpg 格式图片");
        return false;
      }
      return true;
    };

	const onOversize = () => {
      Toast("文件大小不能超过 500kb");
    };

<van-uploader multiple :max-size="onOverSize" />

<van-uploader v-model="fileList" multiple :max-count="4"/>

let photos = []
that.fileList.forEach(v=> {
    let o = {
        base64Str: v.content,
        filename: v.file.name
    }
    photos.push(o)
})

axios.request({
    url: '/x/xxx/api',
    data: {
        photos: photos 
    },
    method: 'POST'
})

@RequestMapping(value = "/api", method = RequestMethod.POST)
public JSONObject xxx(@RequestBody JSONObject jsonObject) {
	JSONArray photos = jsonObject.getJSONArray("photos");
	if (photos.size() > 0) {
        for (int i = 0; i < photos.size(); i++) {
            JSONObject obj = photos.getJSONObject(i);
            String fileName = obj.getString("filename");
            String base64Str = obj.getString("base64Str");
            String directoryName = "xx/xx";
            String extension = fileName.substring(fileName.lastIndexOf(".")).toLowerCase();
            InputStream inputStream = new ByteArrayInputStream(Base64.decodeBase64(base64Str.substring(base64Str.indexOf(",") + 1)));
            OSSClient client = new OSSClient(endpoint, accessKeyId, accessKeySecret);
            client.putObject(bucketName, getRandomKey(directoryName, extension), inputStream);	// extension指的是拓展名，例如".amr"
        }
    }
}
 
/**
 * 随机生成一个key
 * @return String 随机key
 */
public static String getRandomKey(String directoryName, String extension){
    StringBuffer key = new StringBuffer();
	if (StringUtils.isNotBlank(directoryName)) {
	    key.append(directoryName);
		if (directoryName.charAt(directoryName.length() - 1) != '/') {
			key.append("/");
		}
	}
	key.append(System.currentTimeMillis());
	for (int i = 0; i < 10; i++) {
		key.append(randomStr.charAt(RandomUtils.nextInt(0, randomStr.length())));
	}
	if (StringUtils.isNotBlank(extension)) {
		if (extension.indexOf(".") == -1) {
			key.append(".");
		}
		key.append(extension);
	}
	return key.toString();
}