.net core Api上传Txt文档读取并且解决乱码问题

using (StreamReader reader = new StreamReader(strm, Encoding.GetEncoding("GB2312")))
                {

                    string line = null;
                    while ((line = reader.ReadLine()) != null)
                    {
                         //  line是读取到这一行的数据
                    }
                }    

string name = Guid.NewGuid().ToString() + ".txt";
                        string filePath = "/Uploads/txt/" + DateTime.Now.ToString("yyyy-MM-dd") + "/" + name;

                        string rootPath = Directory.GetCurrentDirectory();
                        string path = $@"{rootPath}/Uploads/txt/" + DateTime.Now.ToString("yyyy-MM-dd");
                        string pathRq = $@"/Uploads/txt/" + DateTime.Now.ToString("yyyy-MM-dd") + "/" + name;

                        if (!Directory.Exists(path))
                        {
                            Directory.CreateDirectory(path);
                        }

                        using (FileStream fs = System.IO.File.Create(path + "/" + name))
                        {
                            StreamWriter sw = new StreamWriter(fs);
                            string str = "123456"sw.WriteLine(str);

                            sw.Flush();
                            sw.Close();
                        }

1. 指定读取文件是GB2312
using (StreamReader reader = new StreamReader(strm, Encoding.GetEncoding("GB2312")))
2. 注入：Encoding到容器中
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);