如何在flutter中将excel表格转换为json

Question

如何在flutter中将excel表格转换为json。

我有一张包含学生姓名和班级的 Excel 表，我想将其转换为 json，以便轻松运行应用程序或以其他方式将日期上传到 firestore。

Future<String> excelToJson() async {
var file = await FilePicker.getFilePath(
    type: FileType.custom, allowedExtensions: ['xlsx', 'csv', 'xls']);
var bytes = File(file).readAsBytesSync();
var excel = Excel.decodeBytes(bytes);
int i = 0;
List<dynamic> keys = new List<dynamic>();
List<Map<String, dynamic>> json = new List<Map<String, dynamic>>();
for (var table in excel.tables.keys) {
  for (var row in excel.tables[table].rows) {
    if (i == 0) {
      keys = row;
      i++;
    } else {
      Map<String, dynamic> temp = Map<String, dynamic>();
      int j = 0;
      String tk = '';
      for (var key in keys) {
        tk = "\u201C" + key + "\u201D";
        temp[tk] = (row[j].runtimeType==String)?"\u201C" + row[j].toString() + "\u201D":row[j];
        j++;
      }
      json.add(temp);
    }
  }
}
print(json.length);
String fullJson = json.toString().substring(1, json.toString().length - 1);
return fullJson;}

我想学习如何在我的应用程序中使用这个脚本，或者其他方式更容易和简单

谢谢

Answer 1

使用此方法：

Future<void> excelToJson(String fileName, String fileDirectory,GlobalKey<ScaffoldState> scaffoldKey) async {
  ByteData data = await rootBundle.load(fileDirectory);
  var bytes = data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
  var excel = Excel.decodeBytes(bytes);
  int i = 0;
  List<dynamic> keys = new List<dynamic>();
  List<Map<String, dynamic>> json = new List<Map<String, dynamic>>();
  for (var table in excel.tables.keys) {
    for (var row in excel.tables[table].rows) {
      if (i == 0) {
        keys = row;
        i++;
      } else {
        Map<String, dynamic> temp = Map<String, dynamic>();
        int j = 0;
        String tk = '';
        for (var key in keys) {
          tk = '"' + key + '"';
          temp[tk] = (row[j].runtimeType == String)
              ? '"' + row[j].toString() + '"'
              : row[j];
          j++;
        }
        json.add(temp);
      }
    }
  }
  print(json.length);
  String fullJson = json.toString().substring(1, json
      .toString()
      .length - 1);

  fullJson = '{ "DATA" : [$fullJson]}';
  final directory = await getExternalStorageDirectory();

  File file = await File('${directory.path}/$fileName.json').create();
  await file.writeAsString(fullJson).then((value) =>
      scaffoldKey.currentState
          .showSnackBar(SnackBar(content: Text("Completed")))
  );
  print(file.exists().toString());
}

Future<void> jsonToExcel(String fileName, String fileDirectory,GlobalKey<ScaffoldState> scaffoldKey) async{
  String jsonString = await rootBundle.loadString(fileDirectory);

  List<dynamic> jsonResult = jsonDecode(jsonString)["DATA"];


  var excel = Excel.createExcel();
  Sheet sheetObject = excel['Sheet1'];

  Map<String,dynamic> result = jsonResult[0];
  sheetObject.appendRow(result.keys.toList());

  for(int i =0;i<jsonResult.length;i++){
    Map<String,dynamic> result = jsonResult[i];
    sheetObject.appendRow(result.values.toList());
  }
  final directory = await getExternalStorageDirectory();

  excel.encode().then((onValue) {
    File(("${directory.path}/$fileName.xlsx"))
      ..createSync(recursive: true)
      ..writeAsBytesSync(onValue);
    scaffoldKey.currentState
        .showSnackBar(SnackBar(content: Text("Completed")));
  });


  print(sheetObject);
}

Answer 2

稍微更新了您的代码......

 Future<String> excelToJson() async {
        FilePickerResult result =await FilePicker.platform.pickFiles(type:FileType.custom,allowedExtensions: ['xls','xlsx','csv']);
       if (result != null) {
        File excelFile = File(result.files.single.path);}
        var bytes = File(excelFilePath).readAsBytesSync();
        var excel = Excel.decodeBytes(bytes);
        int i = 0;
        List<dynamic> keys = [];
        var jsonMap = [];
    
        for (var table in excel.tables.keys) {
          dev.log(table.toString());
          for (var row in excel.tables[table].rows) {
            dev.log(row.toString());
            if (i == 0) {
              keys = row;
              i++;
            } else {
              var temp = {};
              int j = 0;
              String tk = '';
              for (var key in keys) {
                tk = '\"${key.toString()}\"';
                temp[tk] = (row[j].runtimeType == String)
                    ?  '\"${row[j].toString()}\"'
                    : row[j];
                j++;
              }
    
              jsonMap.add(temp);
            }
          }
        }
        dev.log(
          jsonMap.length.toString(),
          name: 'excel to json',
        );
        dev.log(jsonMap.toString(), name: 'excel to json');
        String fullJson =
            jsonMap.toString().substring(1, jsonMap.toString().length - 1);
        dev.log(
          fullJson.toString(),
          name: 'excel to json',
        );
        return fullJson;
      }

Answer 3

一般我有两种方法

1. 从内部存储中选择Excel文件 （您可以从任何地方获取，仅限 xlsx 格式）

2. 制作第二种从Excel文件获取列表的方法

        How this will work 
                Here we used PlugIn : [Excel][1] 
                First  get file (excel) from byte ( Uint8List ) format 
                Then Make logic for get data from sheet and convert into json
                After create json/map we store in list and return from method 
   

注意 这里将创建地图，其键取自表标题（第一行）

选择Excel

import 'package:file_picker/file_picker.dart';
import 'package:flutter/services.dart';


Future<Uint8List?> pickExcelCsv({
  String pickTitle = "Pick File",
}) async {
  final picker = FilePicker.platform;


  final FilePickerResult? result = await picker.pickFiles(
    allowCompression: false,
    allowMultiple: false,
    allowedExtensions: [
      'xlsx',
      'csv',
    ],
    type: FileType.custom,
    dialogTitle: pickTitle,
  );


  if (result != null) {
    return result.files.first.bytes;
  }


  return null;
}

getJson/列表

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_excel/excel.dart';


List<Map<String, dynamic>> extractDataFromExcel({required Uint8List bytes}) {
  Excel excel = Excel.decodeBytes(bytes);
  final List<Map<String, dynamic>> result = [];
  final Map<String, dynamic> createMap = {};
  final keys = <String>[];


  // get data from first sheet
  final int n = excel.tables[excel.tables.keys.first]?.rows.length ?? 0;
  debugPrint('n => $n');
  // final List<Data?> rows in excel.tables[excel.tables.keys.first]!.rows
  for (int i = 0; i < n; i++) {
    final rows = excel.tables[excel.tables.keys.first]!.rows[i];
    for (int j = 0; j < rows.length; j++) {
      // index = 0 it will show an header of sheet
      final row = rows[j];
      // Create Header(Keys) for map
      if (i == 0 && row != null) {
        // get header/key from excel and make it list
        keys.add('${row.value}'); // Store key as string
        // Default value is empty
        createMap['${row.value}'] = "";
      }
      // add value in map
      else if (i > 0 && row != null) {
        createMap[keys[j]] = row.value;
      }
    }


    // Now We have make ready
    // we have multiple map/json
    // we we can make list of map/json
    // we add map have key and value both => add if i!=0


    if (i != 0) result.add(Map<String, dynamic>.from(createMap));
  }
  return result;
}

使用

    onTap: () async {
                    final bytes = await pickExcelCsv();
                    if (bytes != null) {
                      final result = extractDataFromExcel(bytes: bytes);
                      debugPrint('### -> $result');
                    }
                  },

结果

Excel 示例

和列表>就像

[
  {
    SrNo: 1,
    FirstName: Dulce,
    LastName: Abril,
    Gender: Female,
    Country: UnitedStates,
    Age: 32,
    Date: 15/10/2017,
    ID: 1562
  },
  {
    SrNo: 2,
    FirstName: Mara,
    LastName: Hashimoto,
    Gender: Female,
    Country: GreatBritain,
    Age: 25,
    Date: 16/08/2016,
    ID: 1582
  },
  {
    SrNo: 3,
    FirstName: Philip,
    LastName: Gent,
    Gender: Male,
    Country: France,
    Age: 36,
    Date: 21/05/2015,
    ID: 2587
  },
  {
    SrNo: 4,
    FirstName: Kathleen,
    LastName: Hanner,
    Gender: Female,
    Country: UnitedStates,
    Age: 25,
    Date: 15/10/2017,
    ID: 3549
  },
  {
    SrNo: 5,
    FirstName: Nereida,
    LastName: Magwood,
    Gender: Female,
    Country: UnitedStates,
    Age: 58,
    Date: 16/08/2016,
    ID: 2468
  },
  {
    SrNo: 6,
    FirstName: Gaston,
    LastName: Brumm,
    Gender: Male,
    Country: UnitedStates,
    Age: 24,
    Date: 21/05/2015,
    ID: 2554
  },
  {
    SrNo: 7,
    FirstName: Etta,
    LastName: Hurn,
    Gender: Female,
    Country: GreatBritain,
    Age: 56,
    Date: 15/10/2017,
    ID: 3598
  },
  {
    SrNo: 8,
    FirstName: Earlean,
    LastName: Melgar,
    Gender: Female,
    Country: UnitedStates,
    Age: 27,
    Date: 16/08/2016,
    ID: 2456
  },
  {
    SrNo: 9,
    FirstName: Vincenza,
    LastName: Weiland,
    Gender: Female,
    Country: UnitedStates,
    Age: 40,
    Date: 21/05/2015,
    ID: 6548
  }
]

希望这对你有帮助！！！