几种文件的读写方式

1.文件写入

string fileName = Path.Combine(LogPath, "log.txt");
Directory.CreateDirectory(LogPath);//创建了文件夹之后，才能创建里面的文件
using (FileStream fileStream = File.Create(fileName))//打开文件流 （创建文件并写入）
{
    string name = "12345567778890";
    byte[] bytes = Encoding.Default.GetBytes(name);
    fileStream.Write(bytes, 0, bytes.Length);
    fileStream.Flush();
}
using (FileStream fileStream = File.Create(fileName))//打开文件流 （创建文件并写入）
{
    StreamWriter sw = new StreamWriter(fileStream);
    sw.WriteLine("1234567890");
    sw.Flush();
}

using (StreamWriter sw = File.AppendText(fileName))//流写入器（创建/打开文件并写入）
{
    string msg = "15663353135";
    sw.WriteLine(msg);
    sw.Flush();
}
using (StreamWriter sw = File.AppendText(fileName))//流写入器（创建/打开文件并写入）
{
    string name = "0987654321";
    byte[] bytes = Encoding.Default.GetBytes(name);
    sw.BaseStream.Write(bytes, 0, bytes.Length);
    sw.Flush();
}

2.文件读取

foreach (string result in File.ReadAllLines(fileName))//逐行读取
{
    Console.WriteLine(result);
}


string sResult = File.ReadAllText(fileName);//一次性读取所有内容，返回字符串


Byte[] byteContent = File.ReadAllBytes(fileName);//一次性读取所有内容，返回字节数组
string sResultByte = System.Text.Encoding.UTF8.GetString(byteContent);//将字节数组转为字符串


//如果一个文本文件太大，可以选择分批读取
using (FileStream stream = File.OpenRead(fileName))//分批读取
{
    int length = 5;
    int result = 0;

    do
    {
        byte[] bytes = new byte[length];
        result = stream.Read(bytes, 0, length);
        for (int i = 0; i < result; i++)
        {
            Console.WriteLine(bytes[i].ToString());
        }
    }
    while (length == result);
}