数据访问之文件系统数据

一：读文件(利用FileStream对象)

using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

namespace ReadFile

{

    class Program

    {

        static void Main(string[] args)

        {

            byte[] byteData = new byte[200];

            char[] charData = new char[200];

            try

            {

                string fileName = "D:\\2.txt";

                FileStream aFile = new FileStream(fileName, FileMode.Open);

                aFile.Seek(113, SeekOrigin.Begin);

                aFile.Read(byteData, 0, 200);

            }

            catch (IOException e)

            {

                Console.WriteLine("A IO Exception has been throw!");

                Console.WriteLine("{0}",e.ToString());

                Console.ReadKey();

                return;

            }

            Decoder decoder = Encoding.UTF8.GetDecoder();

            decoder.GetChars(byteData,0,byteData.Length,charData,0);

            Console.WriteLine("{0}",charData);

            Console.ReadKey();

        }

    }

}

二：写文件(利用FileStream对象)

using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

namespace WriteFile

{

    class Program

    {

        static void Main(string[] args)

        {

            byte[] byteData;

            char[] charData;

            try

            {

                string fileName = "D:\\3.txt";

                FileStream aFile = new FileStream(fileName, FileMode.Create);

                charData = "HelloWorld".ToCharArray();

                byteData = new byte[charData.Length];

                //将字符数组转换为字节数组

                Encoder e = Encoding.UTF8.GetEncoder();

                e.GetBytes(charData, 0, charData.Length, byteData, 0, true);

                aFile.Seek(0, SeekOrigin.Begin);

                aFile.Write(byteData, 0, byteData.Length);

            }

            catch (IOException e)

            {

                Console.WriteLine("A IO Exception has been throw!");

                Console.WriteLine("{0}", e.ToString());

                Console.ReadKey();

                return;

            }

        }

三：利用StreamWriter对象写文件

using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

using System.Data;

namespace StreamWrite

{

    class Program

    {

        static void Main(string[] args)

        {

            try

            {

                FileStream aFile = new FileStream("D:\\Log.txt", FileMode.OpenOrCreate);

                StreamWriter sw = new StreamWriter(aFile);

                bool truth = true;

                sw.WriteLine("Hello!Log!"); 利用WriteLine（）写一行字符串

                sw.WriteLine("It is now {0} and things are longking good.", DateTime.Now.ToLongDateString());

                sw.WriteLine("More than that,");

                sw.Write("it's {0} that c# is fun.", truth);

                sw.Close();

            }

            catch (IOException e)

            {

                Console.WriteLine("A IO Exception has been throw!");

                Console.WriteLine("{0}", e.ToString());

                Console.ReadKey();

                return;

            }

        }

    }

}

    }

}

四：读文件（通过streamreader对象）

using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

namespace StreamRead

{

    class Program

    {

        static void Main(string[] args)

        {

            try

            {

                String fileName = "D:\\Log.txt";

                FileStream fs = new FileStream(fileName, FileMode.Open);

                StreamReader sr = new StreamReader(fs);

                int a = sr.Read();//Read()是读出int型

                Console.WriteLine("{0}", a);

                string b =sr.ReadLine();//ReadLine()来读出字符串型

                while (b != null)

                {

                    Console.WriteLine("{0}", b);

                    b = sr.ReadLine();

                }

                sr.Close();

            }

            catch (IOException e)

            {

                Console.WriteLine("A error !");

                Console.WriteLine(e.ToString());

            }

            Console.ReadKey();

        }

    }

}