C#学习学习笔记的第四篇_验证txt的编码格式,解决读取文件乱码问题
在项目上遇到了读取txt文件乱码,使用的解码格式是Encoding.Default。使用gb2312也是乱码。
后查阅资料发现可以先判断txt文本文件的编码格式,然后再读取
string fileName = @"C:\Users\xongwb\Desktop\ttt.txt"; var tm=GetFileEncodeType(fileName); StreamReader reader = new StreamReader(fileName, tm); var msg = reader.ReadToEnd();
解析文件的编码格式方法
public System.Text.Encoding GetFileEncodeType(string filename) { using (FileStream fs = new FileStream(filename, System.IO.FileMode.Open, System.IO.FileAccess.Read)) { byte[] Unicode = new byte[] { 0xFF, 0xFE, 0x41 }; byte[] UnicodeBIG = new byte[] { 0xFE, 0xFF, 0x00 }; byte[] UTF8 = new byte[] { 0xEF, 0xBB, 0xBF };//带BOM Encoding reVal = Encoding.Default; BinaryReader br = new BinaryReader(fs); int length; int.TryParse(fs.Length.ToString(), out length); byte[] ss = br.ReadBytes(length); if (IsUTF8Bytes(ss) || (ss[0] == UTF8[0] && ss[1] == UTF8[1] && ss[2] == UTF8[2])) reVal = Encoding.UTF8; else if (ss[0] == UnicodeBIG[0] && ss[1] == UnicodeBIG[1] && ss[2] == UnicodeBIG[2]) reVal = Encoding.BigEndianUnicode; else if (ss[0] == Unicode[0] && ss[1] == Unicode[1] && ss[2] == Unicode[2]) reVal = Encoding.Unicode; br.Close(); return reVal; } } /// <summary> /// 判断是否是不带 BOM 的 UTF8 格式 /// </summary> /// <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; } }