Flutter中json.decode解析后数据顺序改变，如何保留插入顺序？

数据老陈

2026-7-16

JSON解析后顺序乱了？教你保留原始插入顺序

为啥会出现乱序？

Dart自带的jsonDecode虽然底层用了LinkedHashMap（理论上该保留插入顺序），但碰到纯数字格式的字符串键时，Dart会自动把这些键当成数字来排序，导致打印或遍历的时候顺序和原始JSON不一致。

解决方案

直接在解析时指定用LinkedHashMap存储数据，通过jsonDecode的reviver参数自定义解析逻辑即可：

修改后的代码示例

import 'dart:convert';
import 'dart:collection';

void main() {
  String jsonResult = '{"113":"13:37:20","155":"13:38:10","157":"13:38:42","159":"13:39:29","161":"13:39:55","163":"13:40:36","165":"13:40:54","135":"13:41:19","137":"13:41:38","139":"13:42:01","141":"13:42:19","143":"13:42:45","145":"13:43:34","147":"13:44:02","149":"13:44:27","0710":"13:48:28","0730":"13:49:12","0750":"13:49:38","0770":"13:50:13","0800":"13:50:45","0810":"13:51:20","0830":"13:55:09","0870":"13:56:41","0900":"14:04:42","1060":"14:17:49"}';
  
  if (jsonResult.isNotEmpty) {
    // 强制用LinkedHashMap保留原始插入顺序
    final jsonData = jsonDecode(jsonResult, reviver: (key, value) {
      if (value is Map) {
        return LinkedHashMap.from(value);
      }
      return value;
    }) as LinkedHashMap<String, dynamic>;
    
    print('#######');
    print(jsonResult);
    print('-----------');
    print(jsonData);
  }
}