如何在Dart中查找大型JSON文件中的值

import 'dart:convert';

import 'dart:io';

void main() {
  File file = File('path/to/json/file.json');
  String jsonString = file.readAsStringSync();
  dynamic jsonData = jsonDecode(jsonString);
}

dynamic findValue(dynamic json, String key) {
  if (json is Map) {
    if (json.containsKey(key)) {
      return json[key];
    } else {
      for (var value in json.values) {
        var result = findValue(value, key);
        if (result != null) {
          return result;
        }
      }
    }
  } else if (json is List) {
    for (var item in json) {
      var result = findValue(item, key);
      if (result != null) {
        return result;
      }
    }
  }
  return null;
}

void main() {
  // 读取JSON文件并解析为Dart对象
  File file = File('path/to/json/file.json');
  String jsonString = file.readAsStringSync();
  dynamic jsonData = jsonDecode(jsonString);

  // 查找目标值
  String targetKey = 'targetKey';
  dynamic targetValue = findValue(jsonData, targetKey);
  if (targetValue != null) {
    print('找到目标值：$targetValue');
  } else {
    print('未找到目标值');
  }
}