Stream转换成byte[] 、将 byte[] 转成 Stream 、Stream和文件的转换、从文件读取 Stream

/* - - - - - - - - - - - - - - - - - - - - - - - -  
 * Stream 和 byte[] 之间的转换 
 * - - - - - - - - - - - - - - - - - - - - - - - */ 
/// <summary> 
/// 将 Stream 转成 byte[] 
/// </summary> 
public byte[] StreamToBytes(Stream stream) 
{ 
    byte[] bytes = new byte[stream.Length]; 
    stream.Read(bytes, 0, bytes.Length); 

    // 设置当前流的位置为流的开始 
    stream.Seek(0, SeekOrigin.Begin); 
    return bytes; 
} 

/// <summary> 
/// 将 byte[] 转成 Stream 
/// </summary> 
public Stream BytesToStream(byte[] bytes) 
{ 
    Stream stream = new MemoryStream(bytes); 
    return stream; 
} 


/* - - - - - - - - - - - - - - - - - - - - - - - -  
 * Stream 和 文件之间的转换 
 * - - - - - - - - - - - - - - - - - - - - - - - */ 
/// <summary> 
/// 将 Stream 写入文件 
/// </summary> 
public void StreamToFile(Stream stream,string fileName) 
{ 
    // 把 Stream 转换成 byte[] 
    byte[] bytes = new byte[stream.Length]; 
    stream.Read(bytes, 0, bytes.Length); 
    // 设置当前流的位置为流的开始 
    stream.Seek(0, SeekOrigin.Begin); 

    // 把 byte[] 写入文件 
    FileStream fs = new FileStream(fileName, FileMode.Create); 
    BinaryWriter bw = new BinaryWriter(fs); 
    bw.Write(bytes); 
    bw.Close(); 
    fs.Close(); 
} 

/// <summary> 
/// 从文件读取 Stream 
/// </summary> 
public Stream FileToStream(string fileName) 
{             
    // 打开文件 
    FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read); 
    // 读取文件的 byte[] 
    byte[] bytes = new byte[fileStream.Length]; 
    fileStream.Read(bytes, 0, bytes.Length); 
    fileStream.Close(); 
    // 把 byte[] 转换成 Stream 
    Stream stream = new MemoryStream(bytes); 
    return stream; 
}