C#_.net core 3.0自定義讀取.csv檔案資料_解決首行不是標題的問題

　　linqtocsv檔案有不太好的地方就是：無法設定標題的行數，默認首行就是標題，這不是很尷尬嗎？并不是所有的csv檔案嚴格寫的首行是標題，下面全是資料，我接受的任務就是讀取很多.csv報表資料，里面就有很多前幾行是說明性內容，下面才是標題和資料，為了更好的解決這個問題，自己寫吧...

　　本博客沒有照搬linqtocsv全部原始碼，保留了主要功能，并對其優化，為我所用，哈哈...

　　下面是主要代碼：

　　1-主檔案CsvHelper：

　　這里在獨自決議資料的時候，遇到了很多坑：

　　a-遇到資料含有分隔符的問題的解決辦法，代碼已經包含了

　　b-遇到了決議源檔案資料時，未指定字符編碼時，部分資料丟失導致csv檔案個別行資料決議例外的問題，針對該問題，就是老老實實把讀取檔案時加了字符編碼的引數進去，默認UTF-8，　　

using Microsoft.Extensions.Logging;
using PaymentAccountAPI.Helper;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;

namespace PaymentAccountAPI.CSV
{
    public class CsvHelper
    {
        /// <summary>
        /// 日志
        /// </summary>
        private ILogger _Logger { get; set; }

        public CsvHelper(ILogger<CsvHelper> logger)
        {
            this._Logger = logger;
        }

        public List<T> Read<T>(string filePath, CsvFileDescription fileDescription) where T : class, new()
        {
            List<T> tList = new List<T>(50 * 10000);

            T t = null;
            int currentRawIndex = 0;

            if (File.Exists(filePath))
            {
                using (StreamReader streamReader = new StreamReader(filePath, fileDescription.Encoding))
                {
                    Dictionary<int, FieldMapper> fieldMapperDic = FieldMapper.GetModelFieldMapper<T>().ToDictionary(m => m.CSVTitleIndex);
                    string rawValue = https://www.cnblogs.com/lxhbky/p/null;
                    string[] rawValueArray = null;
                    PropertyInfo propertyInfo = null;
                    string propertyValue = https://www.cnblogs.com/lxhbky/p/null;
                    bool rawReadEnd = false;

                    bool isExistSplitChart = false;
                    do
                    {
                        rawValue = streamReader.ReadLine();

                        //標題行
                        if (currentRawIndex > fileDescription.TitleRawIndex)
                        {
                            if (!string.IsNullOrEmpty(rawValue))
                            {
                                //替換字串含有分隔符為{分隔符}，最后再替換回來
                                if (rawValue.Contains("\""))
                                {
                                    isExistSplitChart = true;

                                    int yhBeginIndex = 0;
                                    int yhEndIndex = 0;
                                    string yhText = null;
                                    do
                                    {
                                        yhBeginIndex = StringHelper.GetIndexOfStr(rawValue, "\"", 1);
                                        yhEndIndex = StringHelper.GetIndexOfStr(rawValue, "\"", 2);
                                        yhText = rawValue.Substring(yhBeginIndex, (yhEndIndex - yhBeginIndex + 1));
                                        string newYHText = yhText.Replace("\"", "").Replace(fileDescription.SeparatorChar.ToString(), "{分隔符}");
                                        rawValue = rawValue.Replace(yhText, newYHText);
                                    } while (rawValue.Contains("\""));
                                }

                                rawValueArray = rawValue.Split(fileDescription.SeparatorChar);

                                t = new T();
                                foreach (var fieldMapper in fieldMapperDic)
                                {
                                    propertyInfo = fieldMapper.Value.PropertyInfo;
                                    propertyValue = rawValueArray[fieldMapper.Key - 1];
                                    if (!string.IsNullOrEmpty(propertyValue))
                                    {
                                        try
                                        {
                                            if (isExistSplitChart && propertyValue.Contains("{分隔符}"))
                                            {
                                                propertyValue = propertyValue.Replace("{分隔符}", fileDescription.SeparatorChar.ToString());
                                            }

                                            TypeHelper.SetPropertyValue(t, propertyInfo.Name, propertyValue);
                                        }
                                        catch (Exception e)
                                        {
                                            this._Logger.LogWarning(e, $"第{currentRawIndex + 1}行資料{propertyValue}轉換屬性{propertyInfo.Name}-{propertyInfo.PropertyType.Name}失敗！");
                                            continue;
                                        }
                                    }
                                }
                                tList.Add(t);
                            }
                            else
                            {
                                rawReadEnd = true;
                            }
                        }
                        currentRawIndex++;
                    } while (rawReadEnd == false);
                }
            }


            return tList;
        }

        public void WriteFile<T>(string path, List<T> tList, CsvFileDescription fileDescription) where T : class, new()
        {
            if (!string.IsNullOrEmpty(path))
            {
                string fileDirectoryPath = null;
                if (path.Contains("\\"))
                {
                    fileDirectoryPath = path.Substring(0, path.LastIndexOf('\\'));
                }
                else
                {
                    fileDirectoryPath = path.Substring(0, path.LastIndexOf('/'));
                }
                if (!Directory.Exists(fileDirectoryPath))
                {
                    Directory.CreateDirectory(fileDirectoryPath);
                }

                int dataCount = tList.Count;
                Dictionary<int, FieldMapper> fieldMapperDic = FieldMapper.GetModelFieldMapper<T>().ToDictionary(m => m.CSVTitleIndex);
                int titleCount = fieldMapperDic.Keys.Max();
                string[] rawValueArray = new string[titleCount];
                StringBuilder rawValueBuilder = new StringBuilder();
                string rawValue = https://www.cnblogs.com/lxhbky/p/null;
                T t = null;
                PropertyInfo propertyInfo = null;
                int currentRawIndex = 0;
                int tIndex = 0;

                using (StreamWriter streamWriter = new StreamWriter(path, false, fileDescription.Encoding))
                {
                    do
                    {
                        try
                        {
                            rawValue = "";

#if DEBUG
                            if (currentRawIndex % 10000 == 0)
                            {
                                this._Logger.LogInformation($"已寫入檔案：{path}，資料量：{currentRawIndex}");
                            }
#endif

                            if (currentRawIndex >= fileDescription.TitleRawIndex)
                            {
                                //清空陣列資料
                                for (int i = 0; i < titleCount; i++)
                                {
                                    rawValueArray[i] = "";
                                }

                                if (currentRawIndex > fileDescription.TitleRawIndex)
                                {
                                    t = tList[tIndex];
                                    tIndex++;
                                }
                                foreach (var fieldMapperItem in fieldMapperDic)
                                {
                                    //寫入標題行
                                    if (currentRawIndex == fileDescription.TitleRawIndex)
                                    {
                                        rawValueArray[fieldMapperItem.Key - 1] = fieldMapperItem.Value.CSVTitle;
                                    }
                                    //真正的資料從標題行下一行開始寫
                                    else
                                    {
                                        propertyInfo = fieldMapperItem.Value.PropertyInfo;
                                        object propertyValue =https://www.cnblogs.com/lxhbky/p/ propertyInfo.GetValue(t);
                                        string formatValue = https://www.cnblogs.com/lxhbky/p/null;
                                        if (propertyValue != null)
                                        {
                                            if (propertyInfo.PropertyType is IFormattable && !string.IsNullOrEmpty(fieldMapperItem.Value.OutputFormat))
                                            {
                                                formatValue = ((IFormattable)propertyValue).ToString(fieldMapperItem.Value.OutputFormat, null);
                                            }
                                            else
                                            {
                                                formatValue = propertyValue.ToString();
                                            }

                                            //如果屬性值含有分隔符，則使用雙引號包裹
                                            if (formatValue.Contains(fileDescription.SeparatorChar.ToString()))
                                            {
                                                formatValue = $"\"{formatValue}\"";
                                            }
                                            rawValueArray[fieldMapperItem.Key - 1] = formatValue;
                                        }
                                    }
                                }
                                rawValue = string.Join(fileDescription.SeparatorChar, rawValueArray);
                            }
                            rawValueBuilder.Append(rawValue + "\r\n");
                        }
                        catch (Exception e)
                        {
                            this._Logger.LogWarning(e, $"(例外)Excel第{currentRawIndex+1}行，資料串列第{tIndex + 1}個資料寫入失敗！rawValue：{rawValue}");
                            throw;
                        }

                        currentRawIndex++;
                    } while (tIndex < dataCount);
                    streamWriter.Write(rawValueBuilder.ToString());

                    streamWriter.Close();
                    streamWriter.Dispose();
                }
            }
        }

    }
}

　　2-CSV映射類特性：

using System;

namespace PaymentAccountAPI.CSV
{
    /// <summary>
    /// Csv檔案類特性標記
    /// </summary>
    [System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Property, AllowMultiple = false)]
    public class CsvColumnAttribute : System.Attribute
    {
        internal const int defaultTitleIndex = Int32.MaxValue;
        /// <summary>
        /// 標題
        /// </summary>
        public string Title { get; set; }
        /// <summary>
        /// 標題位置（從0開始）
        /// </summary>
        public int TitleIndex { get; set; }
        /// <summary>
        /// 字符輸出格式（數字和日期型別需要）
        /// </summary>
        public string OutputFormat { get; set; }

        public CsvColumnAttribute()
        {
            Title = "";
            TitleIndex = defaultTitleIndex;
            OutputFormat = "";
        }

        public CsvColumnAttribute(string title, int titleIndex, string outputFormat)
        {
            Title = title;
            TitleIndex = titleIndex;
            OutputFormat = outputFormat;
        }
    }
}

　　3-CSV檔案描述資訊類：

using System.Text;

namespace PaymentAccountAPI.CSV
{
    public class CsvFileDescription
    {
        public CsvFileDescription() : this(0)
        {
        }
        public CsvFileDescription(int titleRawIndex) : this(',', titleRawIndex, Encoding.UTF8)
        {
        }
        public CsvFileDescription(char separatorChar, int titleRawIndex, Encoding encoding)
        {
            this.SeparatorChar = separatorChar;
            this.TitleRawIndex = titleRawIndex;
            this.Encoding = encoding;
        }

        /// <summary>
        /// CSV檔案字符編碼
        /// </summary>
        public Encoding Encoding { get; set; }

        /// <summary>
        /// 分隔符（默認為（,）,也可以是其他分隔符如(\t)）
        /// </summary>
        public char SeparatorChar { get; set; }
        /// <summary>
        /// 標題所在行位置（默認為0，沒有標題填-1）
        /// </summary>
        public int TitleRawIndex { get; set; }

    }
}

　　4-映射類獲取關系幫助類：

using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace PaymentAccountAPI.CSV
{
    /// <summary>
    /// 欄位映射類
    /// </summary>
    public class FieldMapper
    {
        /// <summary>
        /// 屬性資訊
        /// </summary>
        public PropertyInfo PropertyInfo { get; set; }
        /// <summary>
        /// 標題
        /// </summary>
        public string CSVTitle { get; set; }
        /// <summary>
        /// 標題下標位置
        /// </summary>
        public int CSVTitleIndex { get; set; }
        /// <summary>
        /// 字符輸出格式（數字和日期型別需要）
        /// </summary>
        public string OutputFormat { get; set; }

        public static List<FieldMapper> GetModelFieldMapper<T>()
        {
            List<FieldMapper> fieldMapperList = new List<FieldMapper>(100);

            List<PropertyInfo> tPropertyInfoList = typeof(T).GetProperties().ToList();
            CsvColumnAttribute csvColumnAttribute = null;
            foreach (var tPropertyInfo in tPropertyInfoList)
            {
                csvColumnAttribute = (CsvColumnAttribute)tPropertyInfo.GetCustomAttribute(typeof(CsvColumnAttribute));
                if (csvColumnAttribute != null)
                {
                    fieldMapperList.Add(new FieldMapper
                    {
                        PropertyInfo = tPropertyInfo,
                        CSVTitle = csvColumnAttribute.Title,
                        CSVTitleIndex = csvColumnAttribute.TitleIndex,
                        OutputFormat = csvColumnAttribute.OutputFormat
                    });
                }
            }
            return fieldMapperList;
        }

    }

}

　　5-其他擴展類：

namespace PaymentAccountAPI.Helper
{
    public class StringHelper
    {
        /// <summary>
        /// 獲取字串中第strPosition個位置的str的下標
        /// </summary>
        /// <param name="text"></param>
        /// <param name="str"></param>
        /// <param name="strPosition"></param>
        /// <returns></returns>
        public static int GetIndexOfStr(string text, string str, int strPosition)
        {
            int strIndex = -1;

            int currentPosition = 0;
            if (!string.IsNullOrEmpty(text) && !string.IsNullOrEmpty(str) && strPosition >= 1)
            {
                do
                {
                    currentPosition++;
                    if (strIndex == -1)
                    {
                        strIndex = text.IndexOf(str);
                    }
                    else
                    {
                        strIndex = text.IndexOf(str, strIndex + 1);
                    }
                } while (currentPosition < strPosition);
            }

            return strIndex;
        }
    }
}

　　最后就是將CsvHelper注入到單例中，就可以使用了...

轉載請註明出處，本文鏈接：https://www.uj5u.com/net/69019.html

標籤：.NET Core

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C#_.net core 3.0自定義讀取.csv檔案資料_解決首行不是標題的問題_Linqtocsv改進