基于NOPI的Execl模板转换类,直接将Execl模板转换对应的Entity

1、创建实体属性标记

  public class CellAttribute : Attribute
     {
         /// <summary>
         ///
         /// </summary>
         /// <param name="displayName">显示名称</param>
         /// <param name="hander"></param>
         public CellAttribute(string displayName, Type hander = null)
         {
             DisplayName = displayName;

             Hander = hander;
         }

         /// <summary>
         /// 显示名称
         /// </summary>
         public string DisplayName { get; set; }

         /// <summary>
         /// 类型
         /// </summary>
         public Type Hander { get; set; }
     }

2、创建通用处理方法

 public class XlsFileHandler<T> where T : new()
     {
         private readonly string _path;
         private readonly Dictionary<string, CellAttribute> _cellAttributes;
         readonly Dictionary<string, string> _propDictionary;

         public XlsFileHandler(string path)
         {
             _path = path;
             _cellAttributes = new Dictionary<string, CellAttribute>();
             _propDictionary = new Dictionary<string, string>();
             CreateMappers();
         }

         /// <summary>
         /// 创建映射
         /// </summary>
         private void CreateMappers()
         {
             foreach (var prop in typeof(T).GetProperties())
             {
                 foreach (CellAttribute cellMapper in prop.GetCustomAttributes(false).OfType<CellAttribute>())
                 {
                     _propDictionary.Add(cellMapper.DisplayName, prop.Name);
                     _cellAttributes.Add(cellMapper.DisplayName, cellMapper);
                 }
             }
         }

         /// <summary>
         /// 获取整个xls文件对应行的T对象
         /// </summary>
         /// <returns></returns>
         public List<T> ToData()
         {
             List<T> dataList = new List<T>();
             using (FileStream stream = GetStream())
             {
                 IWorkbook workbook = new HSSFWorkbook(stream);
                 ISheet sheet = workbook.GetSheetAt();
                 var rows = sheet.GetRowEnumerator();
                 int lastCell = ;
                 int i = ;
                 IRow headRow = null;
                 while (rows.MoveNext())
                 {
                     var row = sheet.GetRow(i);
                     if (i == )
                     {
                         headRow = sheet.GetRow();
                         lastCell = row.LastCellNum;
                     }
                     else
                     {
                         T t = GetData(workbook, headRow, row, lastCell);
                         dataList.Add(t);
                     }
                     i++;
                 }
                 stream.Close();
             }
             return dataList;
         }

         /// <summary>
         /// 获取T对象
         /// </summary>
         /// <param name="workbook"></param>
         /// <param name="headRow"></param>
         /// <param name="currentRow"></param>
         /// <param name="lastCell"></param>
         /// <returns></returns>
         private T GetData(IWorkbook workbook, IRow headRow, IRow currentRow, int lastCell)
         {
             T t = new T();
             for (int j = ; j < lastCell; j++)
             {
                 var displayName = headRow.Cells[j].StringCellValue;
                 if (!_cellAttributes.ContainsKey(displayName) || !_propDictionary.ContainsKey(displayName))
                 {
                     continue;
                 }
                 var currentAttr = _cellAttributes[displayName];
                 var propName = _propDictionary[displayName];

                 ICell currentCell = currentRow.GetCell(j);
                 string value = currentCell != null ? GetCellValue(workbook, currentCell) : "";
                 if (currentAttr.Hander != null)
                 {
                     SetValue(ref t, propName, InvokeHandler(currentAttr.Hander, value));
                 }
                 else
                 {
                     SetValue(ref t, propName, value);
                 }
             }
             return t;
         }

         /// <summary>
         /// 动态执行处理方法
         /// </summary>
         /// <param name="type"></param>
         /// <param name="value"></param>
         /// <returns></returns>
         private static object InvokeHandler(Type type, object value)
         {
             System.Reflection.ConstructorInfo constructor = type.GetConstructor(Type.EmptyTypes);
             if (constructor == null) throw new ArgumentNullException("type");
             object mgConstructor = constructor.Invoke(null);
             System.Reflection.MethodInfo method = type.GetMethod("GetResults");
             return method.Invoke(mgConstructor, new[] { value });
         }

         /// <summary>
         /// 获取文件流
         /// </summary>
         /// <returns></returns>
         private FileStream GetStream()
         {
             if (!File.Exists(_path)) throw new FileNotFoundException("path");
             return new FileStream(_path, FileMode.Open, FileAccess.Read, FileShare.Read);
         }

         /// <summary>
         /// 获取xls文件单元格的值
         /// </summary>
         /// <param name="workbook"></param>
         /// <param name="cell"></param>
         /// <returns></returns>
         private static string GetCellValue(IWorkbook workbook, ICell cell)
         {
             string value;
             switch (cell.CellType)
             {
                 case CellType.FORMULA:
                     HSSFFormulaEvaluator evaluator = new HSSFFormulaEvaluator(workbook);
                     value = evaluator.Evaluate(cell).FormatAsString();
                     break;
                 default:
                     value = cell.ToString();
                     break;
             }
             return value;
         }

         /// <summary>
         /// 设置T属性值
         /// </summary>
         /// <param name="t"></param>
         /// <param name="propName"></param>
         /// <param name="value"></param>
         private static void SetValue(ref T t, string propName, object value)
         {
             var typeName = t.GetType().GetProperty(propName).PropertyType.Name;
             var property = t.GetType().GetProperty(propName);
             switch (typeName)
             {
                 case "Int32":
                     property.SetValue(t, Convert.ToInt32(value), null);
                     break;
                 case "DateTime":
                     property.SetValue(t, Convert.ToDateTime(value), null);
                     break;
                 case "Decimal":
                     property.SetValue(t, Convert.ToDecimal(value), null);
                     break;
                 default:
                     property.SetValue(t, value, null);
                     break;
             }
         }
     }

3、创建Execl文件映射类

 public class ReadMapper
     {
         [CellAttribute("测试1")]
         public decimal Code { get; set; }

         [CellAttribute("测试2")]
         public int Name { get; set; }

         [CellAttribute("测试3", typeof(ClassCellHander))]
         public string Group { get; set; }

         [CellAttribute("测试4")]
         public DateTime AddTime { get; set; }
     }

4、指定Execl文件路径，通过通用处理方法导出映射实体

   [Test]
         public void Read1()
         {
             const string filePath = @"C:\Users\zk\Desktop\1.xls";
             XlsFileHandler<ReadMapper> handler = new XlsFileHandler<ReadMapper>(filePath);
             List<ReadMapper> readMappers = handler.ToData();
             Assert.AreEqual(readMappers.Count, );
         }