c#通过FileStream读取、写入文件

// FileStream读取文件
public static string FileStreamReadFile(string filePath)
{
    byte[] data = new byte[100];
    char[] charData = new char[100];
    FileStream file = new FileStream(filePath, FileMode.Open);
    //文件指针指向0位置
    file.Seek(0, SeekOrigin.Begin);
    //读入两百个字节
    file.Read(data, 0, (int) file.Length);
    //提取字节数组
    Decoder dec = Encoding.UTF8.GetDecoder();
    dec.GetChars(data, 0, data.Length, charData, 0);
    return Convert.ToString(charData);
}

// 用FileStream写文件
public static void FileStreamWriteFile(string filePath, string str)
{
    byte[] byData;
    char[] charData;
    try
    {
        FileStream nFile = new FileStream(filePath + "love.txt", FileMode.Create);
        //获得字符数组
        charData = str.ToCharArray();
        //初始化字节数组
        byData = new byte[charData.Length];
        //将字符数组转换为正确的字节格式
        Encoder enc = Encoding.UTF8.GetEncoder();
        enc.GetBytes(charData, 0, charData.Length, byData, 0, true);
        nFile.Seek(0, SeekOrigin.Begin);
        nFile.Write(byData, 0, byData.Length);
    }
    catch (Exception ex)
    {
        throw ex;
    }
}