.NET Core 2.0如何生成图片验证码完整实例


            前言

图片验证码在我们日常开发中是必不可少会遇见的一个功能，最近工作中就遇到了这个需求，所以下面将实现的方法分享给大家，话不多说了，来一起看看详细的介绍吧。

.NET Core 2.0生成图片验证码

NuGet包引入：ZKWeb.System.Drawing，如下所示：



代码实例如下：VerifyCodeHelper





using System;

using System.DrawingCore;

using System.DrawingCore.Drawing2D;

using System.DrawingCore.Imaging;

using System.IO;

 

namespace Common.Helper

{

 public sealed class VerifyCodeHelper

 {

  #region 单例模式

  //创建私有化静态obj锁 

  private static readonly object _ObjLock = new object();

  //创建私有静态字段，接收类的实例化对象 

  private static VerifyCodeHelper _VerifyCodeHelper = null;

  //构造函数私有化 

  private VerifyCodeHelper() { }

  //创建单利对象资源并返回 

  public static VerifyCodeHelper GetSingleObj()

  {

   if (_VerifyCodeHelper == null)

   {

    lock (_ObjLock)

    {

     if (_VerifyCodeHelper == null)

      _VerifyCodeHelper = new VerifyCodeHelper();

    }

   }

   return _VerifyCodeHelper;

  }

  #endregion

 

  #region 生产验证码

  public enum VerifyCodeType { NumberVerifyCode, AbcVerifyCode, MixVerifyCode };

 

  /// <summary>

  /// 1.数字验证码

  /// </summary>

  /// <param name="length"></param>

  /// <returns></returns>

  private string CreateNumberVerifyCode(int length)

  {

   int[] randMembers = new int[length];

   int[] validateNums = new int[length];

   string validateNumberStr = "";

   //生成起始序列值 

   int seekSeek = unchecked((int)DateTime.Now.Ticks);

   Random seekRand = new Random(seekSeek);

   int beginSeek = seekRand.Next(0, Int32.MaxValue - length * 10000);

   int[] seeks = new int[length];

   for (int i = 0; i < length; i++)

   {

    beginSeek += 10000;

    seeks[i] = beginSeek;

   }

   //生成随机数字 

   for (int i = 0; i < length; i++)

   {

    Random rand = new Random(seeks[i]);

    int pownum = 1 * (int)Math.Pow(10, length);

    randMembers[i] = rand.Next(pownum, Int32.MaxValue);

   }

   //抽取随机数字 

   for (int i = 0; i < length; i++)

   {

    string numStr = randMembers[i].ToString();

    int numLength = numStr.Length;

    Random rand = new Random();

    int numPosition = rand.Next(0, numLength - 1);

    validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));

   }

   //生成验证码 

   for (int i = 0; i < length; i++)

   {

    validateNumberStr += validateNums[i].ToString();

   }

   return validateNumberStr;

  }

 

  /// <summary>

  /// 2.字母验证码

  /// </summary>

  /// <param name="length">字符长度</param>

  /// <returns>验证码字符</returns>

  private string CreateAbcVerifyCode(int length)

  {

   char[] verification = new char[length];

   char[] dictionary = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',

    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'

   };

   Random random = new Random();

   for (int i = 0; i < length; i++)

   {

    verification[i] = dictionary[random.Next(dictionary.Length - 1)];

   }

   return new string(verification);

  }

 

  /// <summary>

  /// 3.混合验证码

  /// </summary>

  /// <param name="length">字符长度</param>

  /// <returns>验证码字符</returns>

  private string CreateMixVerifyCode(int length)

  {

   char[] verification = new char[length];

   char[] dictionary = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',

    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',

    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'

   };

   Random random = new Random();

   for (int i = 0; i < length; i++)

   {

    verification[i] = dictionary[random.Next(dictionary.Length - 1)];

   }

   return new string(verification);

  }

 

  /// <summary>

  /// 产生验证码（随机产生4-6位）

  /// </summary>

  /// <param name="type">验证码类型：数字，字符，符合</param>

  /// <returns></returns>

  public string CreateVerifyCode(VerifyCodeType type)

  {

   string verifyCode = string.Empty;

   Random random = new Random();

   int length = random.Next(4, 6);

   switch (type)

   {

    case VerifyCodeType.NumberVerifyCode:

     verifyCode = GetSingleObj().CreateNumberVerifyCode(length);

     break;

    case VerifyCodeType.AbcVerifyCode:

     verifyCode = GetSingleObj().CreateAbcVerifyCode(length);

     break;

    case VerifyCodeType.MixVerifyCode:

     verifyCode = GetSingleObj().CreateMixVerifyCode(length);

     break;

   }

   return verifyCode;

  }

  #endregion

 

  #region 验证码图片

  /// <summary>

  /// 验证码图片 => Bitmap

  /// </summary>

  /// <param name="verifyCode">验证码</param>

  /// <param name="width">宽</param>

  /// <param name="height">高</param>

  /// <returns>Bitmap</returns>

  public Bitmap CreateBitmapByImgVerifyCode(string verifyCode, int width, int height)

  {

   Font font = new Font("Arial", 14, (FontStyle.Bold | FontStyle.Italic));

   Brush brush;

   Bitmap bitmap = new Bitmap(width, height);

   Graphics g = Graphics.FromImage(bitmap);

   SizeF totalSizeF = g.MeasureString(verifyCode, font);

   SizeF curCharSizeF;

   PointF startPointF = new PointF(0, (height - totalSizeF.Height) / 2);

   Random random = new Random(); //随机数产生器

   g.Clear(Color.White); //清空图片背景色 

   for (int i = 0; i < verifyCode.Length; i++)

   {

    brush = new LinearGradientBrush(new Point(0, 0), new Point(1, 1), Color.FromArgb(random.Next(255), random.Next(255), random.Next(255)), Color.FromArgb(random.Next(255), random.Next(255), random.Next(255)));

    g.DrawString(verifyCode[i].ToString(), font, brush, startPointF);

    curCharSizeF = g.MeasureString(verifyCode[i].ToString(), font);

    startPointF.X += curCharSizeF.Width;

   }

 

   //画图片的干扰线 

   for (int i = 0; i < 10; i++)

   {

    int x1 = random.Next(bitmap.Width);

    int x2 = random.Next(bitmap.Width);

    int y1 = random.Next(bitmap.Height);

    int y2 = random.Next(bitmap.Height);

    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);

   }

 

   //画图片的前景干扰点 

   for (int i = 0; i < 100; i++)

   {

    int x = random.Next(bitmap.Width);

    int y = random.Next(bitmap.Height);

    bitmap.SetPixel(x, y, Color.FromArgb(random.Next()));

   }

 

   g.DrawRectangle(new Pen(Color.Silver), 0, 0, bitmap.Width - 1, bitmap.Height - 1); //画图片的边框线 

   g.Dispose();

   return bitmap;

  }

 

  /// <summary>

  /// 验证码图片 => byte[]

  /// </summary>

  /// <param name="verifyCode">验证码</param>

  /// <param name="width">宽</param>

  /// <param name="height">高</param>

  /// <returns>byte[]</returns>

  public byte[] CreateByteByImgVerifyCode(string verifyCode, int width, int height)

  {

   Font font = new Font("Arial", 14, (FontStyle.Bold | FontStyle.Italic));

   Brush brush;

   Bitmap bitmap = new Bitmap(width, height);

   Graphics g = Graphics.FromImage(bitmap);

   SizeF totalSizeF = g.MeasureString(verifyCode, font);

   SizeF curCharSizeF;

   PointF startPointF = new PointF(0, (height - totalSizeF.Height) / 2);

   Random random = new Random(); //随机数产生器

   g.Clear(Color.White); //清空图片背景色 

   for (int i = 0; i < verifyCode.Length; i++)

   {

    brush = new LinearGradientBrush(new Point(0, 0), new Point(1, 1), Color.FromArgb(random.Next(255), random.Next(255), random.Next(255)), Color.FromArgb(random.Next(255), random.Next(255), random.Next(255)));

    g.DrawString(verifyCode[i].ToString(), font, brush, startPointF);

    curCharSizeF = g.MeasureString(verifyCode[i].ToString(), font);

    startPointF.X += curCharSizeF.Width;

   }

 

   //画图片的干扰线 

   for (int i = 0; i < 10; i++)

   {

    int x1 = random.Next(bitmap.Width);

    int x2 = random.Next(bitmap.Width);

    int y1 = random.Next(bitmap.Height);

    int y2 = random.Next(bitmap.Height);

    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);

   }

 

   //画图片的前景干扰点 

   for (int i = 0; i < 100; i++)

   {

    int x = random.Next(bitmap.Width);

    int y = random.Next(bitmap.Height);

    bitmap.SetPixel(x, y, Color.FromArgb(random.Next()));

   }

 

   g.DrawRectangle(new Pen(Color.Silver), 0, 0, bitmap.Width - 1, bitmap.Height - 1); //画图片的边框线 

   g.Dispose();

 

   //保存图片数据 

   MemoryStream stream = new MemoryStream();

   bitmap.Save(stream, ImageFormat.Jpeg);

   //输出图片流 

   return stream.ToArray();

 

  }

  #endregion

 }

}



新建控制器：VerifyCodeController，





using System.DrawingCore.Imaging;

using System.IO;

using Common.Helper;

using Microsoft.AspNetCore.Mvc;

 

namespace WebApplicationApi.Controllers

{

 public class VerifyCodeController : Controller

 {

  public IActionResult Index()

  {

   return View();

  }

 

  /// <summary>

  /// 数字验证码

  /// </summary>

  /// <returns></returns>

  public FileContentResult NumberVerifyCode()

  {

   string code = VerifyCodeHelper.GetSingleObj().CreateVerifyCode(VerifyCodeHelper.VerifyCodeType.NumberVerifyCode);

   byte[] codeImage = VerifyCodeHelper.GetSingleObj().CreateByteByImgVerifyCode(code, 100, 40);

   return File(codeImage, @"image/jpeg");

  }

 

  /// <summary>

  /// 字母验证码

  /// </summary>

  /// <returns></returns>

  public FileContentResult AbcVerifyCode()

  {

   string code = VerifyCodeHelper.GetSingleObj().CreateVerifyCode(VerifyCodeHelper.VerifyCodeType.AbcVerifyCode);

   var bitmap = VerifyCodeHelper.GetSingleObj().CreateBitmapByImgVerifyCode(code, 100, 40);

   MemoryStream stream = new MemoryStream();

   bitmap.Save(stream, ImageFormat.Png);

   return File(stream.ToArray(), "image/png");

  }

 

  /// <summary>

  /// 混合验证码

  /// </summary>

  /// <returns></returns>

  public FileContentResult MixVerifyCode()

  {

   string code = VerifyCodeHelper.GetSingleObj().CreateVerifyCode(VerifyCodeHelper.VerifyCodeType.MixVerifyCode);

   var bitmap = VerifyCodeHelper.GetSingleObj().CreateBitmapByImgVerifyCode(code, 100, 40);

   MemoryStream stream = new MemoryStream();

   bitmap.Save(stream, ImageFormat.Gif);

   return File(stream.ToArray(), "image/gif");

  }

 

 }

}



添加页面index.cshtml，如下代码：





@{

 Layout = null;

}

<!DOCTYPE html>

<html>

<head>

 <meta name="viewport" content="width=device-width" />

 <title>Index</title>

</head>

<body>

 <figure>

  <h3>图片验证码</h3>

  <fieldset>

   <legend>数字验证码</legend>

   <img id="nubImg" title="数字验证码" src="/VerifyCode/NumberVerifyCode?random=" alt="vcode" onclick="refresh()" style="cursor:pointer;" />

  </fieldset>

  <fieldset>

   <legend>数字验证码</legend>

   <img id="abcImg" title="字母验证码" src="/VerifyCode/AbcVerifyCode" alt="vcode" onclick="this.src=this.src+'?'" style="cursor:pointer;" />

  </fieldset>

  <fieldset>

   <legend>混合验证码</legend>

   <img id="mixImg" title="数字字母混合验证码" src="/VerifyCode/MixVerifyCode" alt="vcode" onclick="this.src=this.src+'?'" style="cursor:pointer;" />

  </fieldset>

 </figure>

 

 <script type="text/javascript">

  function refresh() {

   var id = document.getElementById("nubImg");

   var str = "/VerifyCode/NumberVerifyCode?random=" + Math.random();

   id.setAttribute("src", str);

  }

 </script>

 

</body>

</html>



生成验证码如下所示：



总结

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