对文件的简单操作

1.使用File对象操作文件:

        private static void CreateSimpleFile() {
            string fileName = ".\\test.txt";
            string destFileName = "c:\\test1.txt";

            File.CreateText(fileName);                      //创建新的文件;

            if (!File.Exists(destFileName))                 //判断文件是否存在
            {
                File.Copy(fileName, destFileName, false);   //拷贝文件
            }
            else {
                File.Delete(destFileName);                  //如果已经存在了,则先删除已有文件,再拷贝.
                File.Copy(fileName,destFileName,false);
            }
        }

2.使用StreamWriter和StreamReader操作文件:

        private static void CreateComplexFile() {
            //创建文件,写入内容;
            string fileName = ".\\complexFile.txt";
            StreamWriter writer = new StreamWriter(fileName, false, System.Text.Encoding.GetEncoding("GB2312"));
            writer.WriteLine("Hello StreamWriter!");
            if (writer.Encoding == System.Text.Encoding.GetEncoding("GB2312"))
            {
                writer.WriteLine("swriter.Encoding is GB2312");
            }
            writer.Flush();
            writer.Close();
            //读入文件内容.
            StreamReader reader = new StreamReader(fileName,System.Text.Encoding.GetEncoding("GB2312"),false,1024);
            string line = reader.ReadLine();
            Console.WriteLine(line);
            line = reader.ReadLine();
            Console.WriteLine(line);
            reader.Close();
        }