类别：程序开发
日期：2020-05-03 浏览：2167 评论：0
.csv操作数据类
public class Common
{
/// 给定文件的路径，读取文件的二进制数据，判断文件的编码类型
/// <param name="FILE_NAME">文件路径</param>
/// <returns>文件的编码类型</returns>
public static System.Text.Encoding GetType(string FILE_NAME)
{
System.IO.FileStream fs = new System.IO.FileStream(FILE_NAME, System.IO.FileMode.Open,
System.IO.FileAccess.Read);
System.Text.Encoding r = GetType(fs);
fs.Close();
return r;
}
/// 通过给定的文件流，判断文件的编码类型
/// <param name="fs">文件流</param>
/// <returns>文件的编码类型</returns>
public static System.Text.Encoding GetType(System.IO.FileStream fs)
{
byte[] Unicode = new byte[] { 0xFF, 0xFE, 0x41 };
byte[] UnicodeBIG = new byte[] { 0xFE, 0xFF, 0x00 };
byte[] UTF8 = new byte[] { 0xEF, 0xBB, 0xBF }; //带BOM
System.Text.Encoding reVal = System.Text.Encoding.Default;
System.IO.BinaryReader r = new System.IO.BinaryReader(fs, System.Text.Encoding.Default);
int i;
int.TryParse(fs.Length.ToString(), out i);
byte[] ss = r.ReadBytes(i);
if (IsUTF8Bytes(ss) || (ss[0] == 0xEF && ss[1] == 0xBB && ss[2] == 0xBF))
{
reVal = System.Text.Encoding.UTF8;
}
else if (ss[0] == 0xFE && ss[1] == 0xFF && ss[2] == 0x00)
{
reVal = System.Text.Encoding.BigEndianUnicode;
}
else if (ss[0] == 0xFF && ss[1] == 0xFE && ss[2] == 0x41)
{
reVal = System.Text.Encoding.Unicode;
}
r.Close();
return reVal;
}
/// 判断是否是不带 BOM 的 UTF8 格式
/// <param name="data"></param>
/// <returns></returns>
private static bool IsUTF8Bytes(byte[] data)
{
int charByteCounter = 1; //计算当前正分析的字符应还有的字节数
byte curByte; //当前分析的字节.
for (int i = 0; i < data.Length; i++)
{
curByte = data[i];
if (charByteCounter == 1)
{
if (curByte >= 0x80)
{
//判断当前
while (((curByte <<= 1) & 0x80) != 0)
{
charByteCounter++;
}
//标记位首位若为非0 则至少以2个1开始 如:110XXXXX...........1111110X
if (charByteCounter == 1 || charByteCounter > 6)
{
return false;
}
}
}
else
{
//若是UTF-8 此时第一位必须为1
if ((curByte & 0xC0) != 0x80)
{
return false;
}
charByteCounter--;
}
}
if (charByteCounter > 1)
{
throw new Exception("非预期的byte格式");
}
return true;
}
/// <summary>
/// 从指定url下载csv数据，然后给文件根据下载时间命名，返回文件名
/// </summary>
/// <param name="directory">文件夹路径</param>
/// <param name="url">下载地址</param>
/// <returns>文件名称</returns>
public static string DownloadFile(string directory, string url)
{
try
{
string fileName = CreateFileName(url);
if (!Directory.Exists(directory))//判断指定路径下是否存在指定的文件夹或文件
{
Directory.CreateDirectory(directory);//创建路径下的文件夹
}
WebClient client = new WebClient();
client.DownloadFile(url, directory + fileName);
string datajson=CsvRead(0, directory + fileName);//读取excel表中数据
//另一种方法，将文件地址封装
Dictionary<string, string> dic = new Dictionary<string, string>();
dic.Add("DownExcellocation", directory + fileName);
//csvRead(0, dic["DownExcellocation"]);
return fileName;
}
catch
{
return "";
}
}
public static string DownloadFile(string url)
{
string datajson = CsvRead(4, url);//读取excel表中数据
//另一种方法，将文件地址封装
Dictionary<string, string> dic = new Dictionary<string, string>();
dic.Add("DownExcellocation", url);
return datajson;
}
/// <summary>
/// 创建文件名称
/// </summary>
public static string CreateFileName(string url)
{
string fileName = "";
string fileExt = url.Substring(url.LastIndexOf(".")).Trim().ToLower();
//Random rnd = new Random();
//fileName = DateTime.Now.ToString("yyyyMMddHHmmssfff") + rnd.Next(10, 99).ToString() + fileExt;//获取随机数
fileName = DateTime.Now.ToString("yyyyMMddHHmmssfff") + System.Guid.NewGuid().ToString().Replace("-", "") + fileExt;
return fileName;
}
/// <summary>
/// 将Csv读入DataTable 及返回json数据
/// </summary>
/// <param name="filePath">csv文件路径</param>
/// <param name="n">表示第n行是字段title,第n+1行是记录开始</param>
/// <param name="k">可选参数表示最后K行不算记录默认0</param>
public static string CsvRead(int n, string filePath)
{
DataTable dt = new DataTable();
String csvSplitBy = "(?<=^|,)(\"(?:[^\"]|\"\")*\"|[^,]*)";
StreamReader reader = new StreamReader(filePath, System.Text.Encoding.Default, false);
int i = 0, m = 0;
reader.Peek();
int r = reader.Peek();
while (reader.Peek()-4 > 0)
{
m = m + 1;
string str = reader.ReadLine();
if (m >= n + 1)
{
if (m == n + 1) //如果是字段行，则自动加入字段。
{
MatchCollection mcs = Regex.Matches(str, csvSplitBy);
foreach (Match mc in mcs)
{
dt.Columns.Add(mc.Value); //增加列标题
}
}
else
{
MatchCollection mcs = Regex.Matches(str, "(?<=^|,)(\"(?:[^\"]|\"\")*\"|[^,]*)");
i = 0;
System.Data.DataRow dr = dt.NewRow();
foreach (Match mc in mcs)
{
dr[i] = mc.Value;
i++;
}
dt.Rows.Add(dr); //DataTable 增加一行
}
}
}
// 去掉汇总的后四行数据
for (int t = 1; t <= 4; t++)
{
dt.Rows.Remove(dt.Rows[dt.Rows.Count - 1]);
}
string excelJson = DataTableToJson(dt);
//Console.WriteLine(excelJson);
return excelJson;
}
/// <summary>
/// 将Csv读入DataTable 及返回json数据
/// </summary>
/// <param name="filePath">csv文件路径</param>
/// <param name="n">表示第n行是字段title,第n+1行是记录开始</param>
/// <param name="k">可选参数表示最后K行不算记录默认0</param>
public static DataTable CsvReadBydt(int n, string filePath)
{
DataTable dt = new DataTable();
String csvSplitBy = "(?<=^|,)(\"(?:[^\"]|\"\")*\"|[^,]*)";
StreamReader reader = new StreamReader(filePath, System.Text.Encoding.Default, false);
int i = 0, m = 0;
reader.Peek();
while (reader.Peek() > 0)
{
m = m + 1;
string str = reader.ReadLine();
if (m >= n + 1)
{
if (m == n + 1) //如果是字段行，则自动加入字段。
{
MatchCollection mcs = Regex.Matches(str, csvSplitBy);
foreach (Match mc in mcs)
{
dt.Columns.Add(mc.Value); //增加列标题
}
}
else
{
MatchCollection mcs = Regex.Matches(str, "(?<=^|,)(\"(?:[^\"]|\"\")*\"|[^,]*)");
i = 0;
System.Data.DataRow dr = dt.NewRow();
foreach (Match mc in mcs)
{
dr[i] = mc.Value;
i++;
}
dt.Rows.Add(dr); //DataTable 增加一行
}
}
}
return dt;
}
#region 帮助类DataSet转换为Json
/// <summary>
/// DataSet转换为Json
/// </summary>
/// <param name="dataSet">DataSet对象</param>
/// <returns>Json字符串</returns>
public static string DataSetToJson(DataSet dataSet)
{
string jsonString = "{";
foreach (DataTable table in dataSet.Tables)
{
jsonString += "\"" + table.TableName + "\":" + DataTableToJson(table) + ",";
}
jsonString = jsonString.TrimEnd(',');
return jsonString + "}";
}
#endregion
#region 帮助类Datatable转换为Json
/// <summary>
/// Datatable转换为Json
/// </summary>
/// <param name="table">Datatable对象</param>
/// <returns>Json字符串</returns>
public static string DataTableToJson(DataTable dt)
{
StringBuilder jsonString = new StringBuilder();
jsonString.Append("[");
DataRowCollection drc = dt.Rows;
for (int i = 0; i < drc.Count; i++)
{
jsonString.Append("{");
for (int j = 0; j < dt.Columns.Count; j++)
{
string strKey = dt.Columns[j].ColumnName;
string strValue = drc[i][j].ToString();
Type type = dt.Columns[j].DataType;
jsonString.Append("\"" + strKey + "\":");
strValue = StringFormat(strValue, type);
if (j < dt.Columns.Count - 1)
{
jsonString.Append(strValue + ",");
}
else
{
jsonString.Append(strValue);
}
}
jsonString.Append("},");
}
jsonString.Remove(jsonString.Length - 1, 1);
jsonString.Append("]");
return jsonString.ToString();
}
#endregion
#region 帮助类格式化字符型、日期型、布尔型StringFormat
/// <summary>
/// 格式化字符型、日期型、布尔型
/// </summary>
/// <param name="str"></param>
/// <param name="type"></param>
/// <returns></returns>
private static string StringFormat(string str, Type type)
{
if (type == typeof(string))
{
str = String2Json(str);
str = "\"" + str + "\"";
}
else if (type == typeof(DateTime))
{
str = "\"" + str + "\"";
}
else if (type == typeof(bool))
{
str = str.ToLower();
}
else if (type != typeof(string) && string.IsNullOrEmpty(str))
{
str = "\"" + str + "\"";
}
return str;
}
#endregion
#region 过滤特殊字符String2Json(String s)
/// <summary>
/// 过滤特殊字符
/// </summary>
/// <param name="s">字符串</param>
/// <returns>json字符串</returns>
private static string String2Json(String s)
{
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
char c = s.ToCharArray()[i];
switch (c)
{
case '\"':
sb.Append("\\\""); break;
case '\\':
sb.Append("\\\\"); break;
case '/':
sb.Append("\\/"); break;
case '\b':
sb.Append("\\b"); break;
case '\f':
sb.Append("\\f"); break;
case '\n':
sb.Append("\\n"); break;
case '\r':
sb.Append("\\r"); break;
case '\t':
sb.Append("\\t"); break;
default:
sb.Append(c); break;
}
}
return sb.ToString();
}
#endregion
}调用方式
string json = Common.DownloadFile(".csv文件路径");
本文标题：C# 如何操作.csv文件？
本文链接：https://vtzw.com/post/176.html
版权声明：本文不使用任何协议授权，您可以任何形式自由转载或使用。
您阅读本篇文章共花了： 
发表评论 / 取消回复