1.数据库选型

flutter项目，需要使用本地存储，面临三个选择

• shared_preferences
• sqflite
• hive
  第一个只能保存key vaule，用起来比较不爽。
  
  第二个对桌面版的不支持。
  
  最后选择了hive，用起来还算可以，不过，相对于后台的orm，还是有些东西需要自己处理。

2.hive的简单使用

之前做个一阵子后台，按照后台的orm逻辑，组装了一下hive。

main.dart里面初始化hive

void main() async {
  await InitHive();
  runApp(const MyApp());

}

hive的初始化部分，初始化了三张表

late Box MClients;
late Box MsgInfos;
late Box TopicInfos;

Future<void> InitHive() async {
  var databasesPath = await getApplicationSupportDirectory();
  //Hive.init('./');
  print(databasesPath.path);
  await Hive.initFlutter(databasesPath.path + '/data');
  Hive.registerAdapter(MClientAdapter());
  Hive.registerAdapter(MsgInfoAdapter());
  Hive.registerAdapter(TopicInfoAdapter());

  MClients = await Hive.openBox<MClient>('mclients');
  MsgInfos = await Hive.openBox<MsgInfo>('msginfos');
  TopicInfos = await Hive.openBox<TopicInfo>('topicinfos');
}

单个表的model

@HiveType(typeId: 1)
class MClient {
  @HiveField(0)
  String? clientid;
  @HiveField(1)
  String? host;
  @HiveField(2)
  String? port;
  @HiveField(3)
  String? user;
  @HiveField(4)
  String? password;
  MClient({this.clientid, this.host, this.port, this.user, this.password});
}

class MClientAdapter extends TypeAdapter<MClient> {
  @override
  final typeId = 0;

  @override
  MClient read(BinaryReader reader) {
    return MClient()
      ..clientid = reader.read()
      ..host = reader.read()
      ..password = reader.read()
      ..user = reader.read()
      ..password = reader.read();
  }

  @override
  void write(BinaryWriter writer, MClient obj) {
    writer.write(obj.clientid);
    writer.write(obj.host);
    writer.write(obj.port);
    writer.write(obj.user);
    writer.write(obj.password);
  }
}

void clientCreate(clientid, host, port, user, password) {
  var cc = MClient(
      clientid: clientid,
      host: host,
      port: port,
      user: user,
      password: password);
  MClients.put(clientid, cc);
}

MClient? clientGet(clientid) {
  if (MClients.get(clientid) != null) {
    var cc1 = MClients.get(clientid);
    return cc1;
  } else {
    return null;
  }
}

List<MClient> clientGetList() {
  var res = MClients.values.toList();
  List<MClient> cc = res.cast<MClient>();
  print("查到list:  $cc");
  return cc;
}

void clientDel(clientid) {
  MClients.delete(clientid);
}

使用model

late List<String> clientids;
getClientids() {
    clients = ClientGetList();
    clientidsd =
        List.generate(clients.length, (index) => clients[index].clientid);
    clientids = clientidsd.cast<String>();
  }

结束