oracle汉字乱码

//读出时进行转换 
                public static string ISO8859_GB2312(string read) 
                { 
                        //声明字符集 
                        System.Text.Encoding iso8859,gb2312; 
                        //iso8859 
                        iso8859 = System.Text.Encoding.GetEncoding("iso8859-1"); 
                        //国标2312 
                        gb2312 = System.Text.Encoding.GetEncoding("gb2312"); 
                        byte[] iso; 
                        iso = iso8859.GetBytes(read); 
                        //返回转换后的字符 
                        return gb2312.GetString(iso); 
                }