ASP.NET中文验证码详解
汉字验证码技术:它比字母跟数字混合技术更先进。主要用过生成汉字的区位码将其转换为汉字,区位码是汉字一一对应的编码。用4为数字表示,前面两位从01到94成为区码,同理后面两位成为位码。懒得打字就贴出出要的程序,如有问题请联系我QQ:1264373.
CheckCode.aspx.cs:
CheckCode.aspx.cs:
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public partial class _Default : System.Web.UI.Page
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{
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protected void Page_Load(object sender, EventArgs e)
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{
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GraphicsImage(4); //调用方法生成四位汉字验证码
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}
7![](/Images/OutliningIndicators/InBlock.gif)
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private object[] CreateString(int strlength)
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{
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//定义一个数组存储汉字编码的组成元素
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string[] str = new string[16] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
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"e", "f" };
13![](/Images/OutliningIndicators/InBlock.gif)
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Random ran = new Random(); //定义一个随机数对象
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object[] bytes = new object[strlength];
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for (int i = 0; i < strlength; i++)
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{
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//获取区位码第一位
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int ran1 = ran.Next(11, 14);
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string str1 = str[ran1].Trim();
21![](/Images/OutliningIndicators/InBlock.gif)
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//获取区位码第二位并防止数据重复
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ran = new Random(ran1 * unchecked((int)DateTime.Now.Ticks) + i);
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int ran2;
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if (ran1 == 13)
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{
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ran2 = ran.Next(0, 7);
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}
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else
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{
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ran2 = ran.Next(0, 16);
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}
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string str2 = str[ran2].Trim();
34![](/Images/OutliningIndicators/InBlock.gif)
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//获取区位码第三位
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ran = new Random(ran2 * unchecked((int)DateTime.Now.Ticks) + i);
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int ran3 = ran.Next(10, 16);
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string str3 = str[ran3].Trim();
39![](/Images/OutliningIndicators/InBlock.gif)
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//获取区位码第四位
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ran = new Random(ran3 * unchecked((int)DateTime.Now.Ticks) + i);
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int ran4;
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if (ran3 == 10)
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{
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ran4 = ran.Next(1, 16);
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}
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else if (ran3 == 15)
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{
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ran4 = ran.Next(0, 15);
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}
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else
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{
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ran4 = ran.Next(0, 16);
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}
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string str4 = str[ran4].Trim();
56![](/Images/OutliningIndicators/InBlock.gif)
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//定义字节变量存储产生的随机汉字区位码
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byte byte1 = Convert.ToByte(str1 + str2, 16);
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byte byte2 = Convert.ToByte(str3 + str4, 16);
60![](/Images/OutliningIndicators/InBlock.gif)
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byte[] stradd = new byte[] { byte1,byte2};
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//将产生的汉字字节放入数组
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bytes.SetValue(stradd, i);
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}
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return bytes;
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}
67![](/Images/OutliningIndicators/InBlock.gif)
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private string GetString(int length)
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{
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Encoding gb = Encoding.GetEncoding("gb2312");
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object[] bytes = CreateString(length);
72![](/Images/OutliningIndicators/InBlock.gif)
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//根据汉字字节解码出中文汉字
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string str1 = gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[])));
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string str2 = gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[])));
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string str3 = gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[])));
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string str4 = gb.GetString((byte[])Convert.ChangeType(bytes[3], typeof(byte[])));
78![](/Images/OutliningIndicators/InBlock.gif)
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string str = str1 + str2 + str3 + str4;
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Response.Cookies.Add(new HttpCookie("CheckCode", str));
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return str;
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}
83![](/Images/OutliningIndicators/InBlock.gif)
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private void GraphicsImage(int length)
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{
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System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((GetString(length).Length *
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22.5)), 22);
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Graphics g = Graphics.FromImage(image); //创建画布
89![](/Images/OutliningIndicators/InBlock.gif)
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try
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{
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//生成随机生成器
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Random random = new Random();
94![](/Images/OutliningIndicators/InBlock.gif)
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//清空图片背景色
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g.Clear(Color.White);
97![](/Images/OutliningIndicators/InBlock.gif)
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//画图片的背景噪音线
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for (int i = 0; i < 1; i++)
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{
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int x1 = random.Next(image.Width);
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int x2 = random.Next(image.Width);
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int y1 = random.Next(image.Height);
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int y2 = random.Next(image.Height);
105![](/Images/OutliningIndicators/InBlock.gif)
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g.DrawLine(new Pen(Color.Black), x1, y1, x2, y2);
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}
108![](/Images/OutliningIndicators/InBlock.gif)
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Font font = new System.Drawing.Font("Couriew New", 12, System.Drawing.FontStyle.Bold );
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System.Drawing.Drawing2D.LinearGradientBrush brush = new
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System.Drawing.Drawing2D.LinearGradientBrush
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(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
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g.DrawString(GetString(length), font, brush, 2, 2);
114![](/Images/OutliningIndicators/InBlock.gif)
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//画图片的前景噪音点
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for (int i = 0; i < 50; i++)
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{
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int x = random.Next(image.Width);
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int y = random.Next(image.Height);
120![](/Images/OutliningIndicators/InBlock.gif)
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image.SetPixel(x, y, Color.FromArgb(random.Next()));
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}
123![](/Images/OutliningIndicators/InBlock.gif)
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//画图片的边框线
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g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
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System.IO.MemoryStream ms = new System.IO.MemoryStream();
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image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
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Response.ClearContent();
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Response.ContentType = "image/Gif";
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Response.BinaryWrite(ms.ToArray());
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}
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catch (Exception ms)
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{
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Response.Write(ms.Message);
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}
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}
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}
138![](/Images/OutliningIndicators/None.gif)
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protected void Button1_Click(object sender, EventArgs e)
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{
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HttpCookie cookie = Request.Cookies["CheckCode"];
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if (cookie.Value == this.TextBox3.Text.Trim())
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{
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Response.Write("<script>alert('验证码正确!')</script>");
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}
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else
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{
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Response.Write("<script>alert('验证码错误!')</script>");
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}
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}
![](/Images/OutliningIndicators/None.gif)
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