Base64编码和解码

C#中的实现

编码：

byte[] bytes = Encoding.Default.GetBytes("要转换的字符"); //gb2312  如需utf-8   Encoding.utf-8.GetBytes();
string str = Convert.ToBase64String(bytes);

 

解码：

byte[] outputb= Convert.FromBase64String(str);
string orgStr= Encoding.Default.GetString(outputb);

 

C#图片的Base64编码和解码

图片的Base64编码：

System.IO.MemoryStream m= new System.IO.MemoryStream();
System.Drawing.Bitmap bp =new System.Drawing.Bitmap(@“c:\demo.GIF”);
bp.Save(m, System.Drawing.Imaging.ImageFormat.Gif);
byte[]b= m.GetBuffer();
string base64string=Convert.ToBase64String(b);

Base64字符串解码：

byte[] bt= Convert.FromBase64String(base64string);
System.IO.MemoryStream stream =new System.IO.MemoryStream(bt);
Bitmap bitmap =new Bitmap(stream);
pictureBox1.Image = bitmap;

 

通用方式

/// <summary>
        /// 对任意类型的文件进行base64加码
        /// </summary>
        /// <param name="filePath">文件的路径和文件名 </param>
        /// <returns>对文件进行base64编码后的字符串 </returns>
        public static string FileToString(string filePath)
        {
            if (!string.IsNullOrEmpty(filePath) && File.Exists(filePath))
            {
                System.IO.FileStream fs = System.IO.File.OpenRead(filePath);
                System.IO.BinaryReader br = new System.IO.BinaryReader(fs);

                string base64String = Convert.ToBase64String(br.ReadBytes((int)fs.Length));

                br.Close();
                fs.Close();
                return base64String;
            }
            else
            {
                return "";
            }
        }

  /// <summary>
        /// 把经过base64编码的字符串保存为文件
        /// </summary>
        /// <param name="base64String">经base64加码后的字符串 </param>
        /// <param name="fileName">保存文件的路径和文件名 </param>
        /// <returns>保存文件是否成功 </returns>
        public static bool StringToFile(string base64String, string fileName)
        {
            //string path = Path.GetDirectoryName(Assembly.GetExecutingAssembly().GetName().CodeBase) + @"/beapp/" + fileName;
         
            System.IO.FileStream fs = new System.IO.FileStream(fileName, System.IO.FileMode.Create);
            System.IO.BinaryWriter bw = new System.IO.BinaryWriter(fs);
            if (!string.IsNullOrEmpty(base64String) && File.Exists(fileName))
            {
                bw.Write(Convert.FromBase64String(base64String));
            }
            bw.Close();
            fs.Close();
            return true;
        }