開發工具：eclipse、kaptcha-2.3.jar包。
一、創建Web項目；
二、新建一個Jsp頁面（內容有，一個文本框，一個圖片容器，一個提交按鈕)
<body> <img alt="random" src="randomcode.jpg" onclick="changeR(this)" style="cursor: pointer;"> <form action="check.jsp"> <input type="text" name="r"> <input type="submit" value="s"> </form> </body>
三、可以看出圖片驗證碼來源（src=“randomcode.jpg”）需配置Web.xml文件。（交給Servlet（該servlet在kaptcha-2.3.jar）處理）
<servlet> <servlet-name>Kaptcha</servlet-name> <servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>Kaptcha</servlet-name> <url-pattern>/randomcode.jpg</url-pattern> </servlet-mapping>
四、由于需要kaptcha-2.3.jar包，所以將下載好的jar包導入在lib中。（復制黏貼即可）
其他：
一、網頁驗證碼的屬性
（一）添加邊框
<servlet> <init-param> <description>圖片邊框，合法值：yes , no</description> <param-name>kaptcha.border</param-name> <param-value>yes</param-value> <!-- yes 或者 no--> </init-param> </servlet>
（二）邊框顏色
<init-param> <description> 邊框顏色，合法值： r,g,b (and optional alpha) 或者white,black,blue. </description> <param-name>kaptcha.border.color</param-name> <param-value>black</param-value> </init-param>
（三）邊框厚度
<init-param> <description>邊框厚度，合法值：>大于0 </description> <param-name>kaptcha.border.thickness</param-name> <param-value>1</param-value> </init-param>
（四）圖片寬度
<init-param> <description>圖片寬 200</description> <param-name>kaptcha.image.width</param-name> <param-value>200</param-value> </init-param>
（五）圖片高度
<init-param> <description>圖片高 50</description> <param-name>kaptcha.image.height</param-name> <param-value>50</param-value> </init-param>
（六）驗證碼集合
<init-param> <description>文本集合，驗證碼值從此集合中獲取</description> <param-name>kaptcha.textproducer.char.string</param-name> <param-value>1234567890</param-value> <!--純數字 --> //<param-value>abcde2345678gfynmnpwx</param-value> <!-- 文字加英文--> </init-param>
（七）驗證碼長度
<init-param> <description>驗證碼長度 默認是5 </description> <param-name>kaptcha.textproducer.char.length</param-name> <param-value>2</param-value> </init-param>
（八）字體
<init-param> <description>字體 Arial, Courier</description> <param-name>kaptcha.textproducer.font.names</param-name> <param-value>Arial, Courier</param-value> </init-param>
（九）字體大小
<init-param> <description>字體大小 40px.</description> <param-name>kaptcha.textproducer.font.size</param-name> <param-value>40</param-value> </init-param>
（十）字體顏色
<init-param> <description> 字體顏色，合法值： r,g,b 或者 white,black,blue. </description> <param-name>kaptcha.textproducer.font.color</param-name> <param-value>black</param-value> </init-param>
（十一）每個驗證碼之間的間隔
<init-param> <description>文字間隔 2</description> <param-name>kaptcha.textproducer.char.space</param-name> <param-value>2</param-value> </init-param>
（十二）干擾實現
<init-param> <description>干擾實現類</description> <param-name>kaptcha.noise.impl</param-name> <param-value> <!-- com.google.code.kaptcha.impl.NoNoise --> com.google.code.kaptcha.impl.DefaultNoise </param-value> </init-param>
（十三）干擾顏色
<init-param> <description> 干擾顏色，合法值： r,g,b 或者 white,black,blue. </description> <param-name>kaptcha.noise.color</param-name> <param-value>black</param-value> </init-param>
（十四）背景樣式
<init-param> <description> 圖片樣式： 水紋com.google.code.kaptcha.impl.WaterRipple 魚眼com.google.code.kaptcha.impl.FishEyeGimpy 陰影com.google.code.kaptcha.impl.ShadowGimpy </description> <param-name>kaptcha.obscurificator.impl</param-name> <param-value> com.google.code.kaptcha.impl.WaterRipple </param-value> </init-param>
（十五）背景實現類
<init-param> <description>背景實現類</description> <param-name>kaptcha.background.impl</param-name> <param-value> com.google.code.kaptcha.impl.DefaultBackground </param-value> </init-param>
（十六）背景漸變顏色
<init-param> <description>背景顏色漸變，開始顏色</description> <param-name>kaptcha.background.clear.from</param-name> <param-value>green</param-value> </init-param> <init-param> <description>背景顏色漸變，結束顏色</description> <param-name>kaptcha.background.clear.to</param-name> <param-value>white</param-value> </init-param>
（十七）文字渲染器
<init-param> <description> 文字渲染器 </description> <param-name>kaptcha.word.impl</param-name> <param-value> com.google.code.kaptcha.text.impl.DefaultWordRenderer</param-value> </init-param>
（十八）圖片的驗證碼會保存在Session中，其中的值為
<init-param> <description> session中存放驗證碼的key鍵 </description> <param-name>kaptcha.session.key</param-name> <param-value>KAPTCHA_SESSION_KEY</param-value> </init-param>
（十九）圖片實現類別
<init-param> <description>圖片實現類</description> <param-name>kaptcha.producer.impl</param-name> <param-value> com.google.code.kaptcha.impl.DefaultKaptcha </param-value> </init-param>
（二十）文本實現類（可通過重寫該類來實現驗證碼為中文）
<init-param> <description>文本實現類</description> <param-name>kaptcha.textproducer.impl</param-name> <param-value> com.google.code.kaptcha.text.impl.DefaultTextCreator </param-value> </init-param>
重寫文本實現類，實現驗證碼為中文：
1.創建一個類別，繼承Configurable 實現TextProducer（在jar包中）
import com.google.code.kaptcha.text.TextProducer; import com.google.code.kaptcha.util.Configurable; import java.util.Random; public class ChineseText extends Configurable implements TextProducer { public String getText() { int length = getConfig().getTextProducerCharLength(); String finalWord = "", firstWord = ""; int tempInt = 0; String[] array = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" }; Random rand = new Random(); for (int i = 0; i < length; i++) { switch (rand.nextInt(array.length)) { case 1: tempInt = rand.nextInt(26) + 65; firstWord = String.valueOf((char) tempInt); break; case 2: int r1, r2, r3, r4; String strH, strL;// high&low r1 = rand.nextInt(3) + 11; // 前閉后開[11,14) if (r1 == 13) { r2 = rand.nextInt(7); } else { r2 = rand.nextInt(16); } r3 = rand.nextInt(6) + 10; if (r3 == 10) { r4 = rand.nextInt(15) + 1; } else if (r3 == 15) { r4 = rand.nextInt(15); } else { r4 = rand.nextInt(16); } strH = array[r1] + array[r2]; strL = array[r3] + array[r4]; byte[] bytes = new byte[2]; bytes[0] = (byte) (Integer.parseInt(strH, 16)); bytes[1] = (byte) (Integer.parseInt(strL, 16)); firstWord = new String(bytes); break; default: tempInt = rand.nextInt(10) + 48; firstWord = String.valueOf((char) tempInt); break; } finalWord += firstWord; } return finalWord; } }2.修改Web.xml配置
<init-param> <description>文本實現類</description> <param-name>kaptcha.textproducer.impl</param-name> <param-value> ChineseText </param-value> </init-param> 五、驗證碼的校驗（本文是利用check.jsp來校驗的）保存在Session中，其中的鍵值為（第十八個屬性）[html] view plain copy<body> <% // 檢查是否是正確的驗證碼 String k = (String) session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY); String str = request.getParameter("r"); if (k.equals(str)) out.print("true"); out.print(k + "---" + str); %> </body>六、擴展（加法驗證碼的實現）
1.重寫KaptchaServlet類
import com.google.code.kaptcha.Producer; import com.google.code.kaptcha.util.Config; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Enumeration; import java.util.Properties; import javax.imageio.ImageIO; import javax.servlet.Servlet; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; public class KaptchaServlet extends HttpServlet implements Servlet { private Properties props; private Producer kaptchaProducer; private String sessionKeyValue; public KaptchaServlet() { this.props = new Properties(); this.kaptchaProducer = null; this.sessionKeyValue = null; } public void init(ServletConfig conf) throws ServletException { super.init(conf); ImageIO.setUseCache(false); Enumeration initParams = conf.getInitParameterNames(); while (initParams.hasMoreElements()) { String key = (String) initParams.nextElement(); String value = conf.getInitParameter(key); this.props.put(key, value); } Config config = new Config(this.props); this.kaptchaProducer = config.getProducerImpl(); this.sessionKeyValue = config.getSessionKey(); } public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setDateHeader("Expires", 0L); resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate"); resp.addHeader("Cache-Control", "post-check=0, pre-check=0"); resp.setHeader("Pragma", "no-cache"); resp.setContentType("image/jpeg"); String capText = this.kaptchaProducer.createText(); String s1 = capText.substring(0, 1); String s2 = capText.substring(1, 2); int r = Integer.valueOf(s1).intValue() + Integer.valueOf(s2).intValue(); req.getSession().setAttribute(this.sessionKeyValue, String.valueOf(r)); BufferedImage bi = this.kaptchaProducer.createImage(s1+"+"+s2+"=?"); ServletOutputStream out = resp.getOutputStream(); ImageIO.write(bi, "jpg", out); try { out.flush(); } finally { out.close(); } } }2.修改配置文件
<servlet> <servlet-name>Kaptcha</servlet-name> <servlet-class>KaptchaServlet</servlet-class> </servlet>
以上所述是小編給大家介紹的使用開源工具制作網頁驗證碼的方法，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對武林網網站的支持！
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