最近博客园的改版动作比较大，看到后台管理页面的验证码，提起了我的兴趣。点击显示的验证码，可以进入到一个专门做验证码的网站：http://captcha.com/
其中包含有java、php、.net等，几乎是全平台支持的，还有配套的教程和demo。
文末提供下载下来的java版的文件，里面有jar包，如何使用呢？想快速入手：
一：最简单的文字验证码。使用jsp方式。
在jsp页面引用：
<%@page import="botdetect.web.Captcha"%>
然后在需要验证码的地方加上:
<%
// Adding BotDetect Captcha to the page
Captcha captcha = Captcha.load(request, "exampleCaptcha");
captcha.renderCaptchaMarkup(pageContext.getServletContext(),
pageContext.getOut());
%>
<input id="captchaCodeTextBox" type="text" name="captchaCodeTextBox" />
检测用户输入的验证码是否正确
<%
if("POST".equalsIgnoreCase(request.getMethod())){
// validate the Captcha to check we‘re not dealing with a bot
boolean isHuman = captcha.validate(request,
request.getParameter("captchaCodeTextBox"));
if(isHuman){
// TODO: Captcha validation passed, perform protected action
} else {
// TODO: Captcha validation failed, show error message
}
}
%>
既然引入了第三方jar包，当然少不了在web.xml中配置了。
<servlet-name>BotDetect Captcha</servlet-name>
<servlet-class>botdetect.web.http.CaptchaServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>BotDetect Captcha</servlet-name>
<url-pattern>/botdetectcaptcha</url-pattern>
</servlet-mapping>
二：使用SpringMVC方式。
对应的页面：
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="botDetect" uri="botDetect"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>BotDetect CAPTCHA Spring MVC Basic Example</title>
<link rel="stylesheet" href="stylesheet.css" type="text/css"/>
</head>
<body>
<form method="post">
<h1>BotDetect CAPTCHA Spring MVC Basic Example</h1>
<fieldset>
<legend>CAPTCHA Validation</legend>
<label for="captchaCodeTextBox" class="prompt">
Retype the code from the picture:</label>
<!-- Adding BotDetect Captcha to the page -->
<botDetect:captcha id="basicExampleCaptcha"/>
<div class="validationDiv">
<input id="captchaCodeTextBox" type="text"
name="captchaCodeTextBox"
value="${basicExample.captchaCodeTextBox}"/>
<input type="submit" name="submit" value="Submit" />
<span class="correct">${basicExample.captchaCodeCorrect}</span>
<span class="incorrect">${basicExample.captchaCodeIncorrect}</span>
</div>
</fieldset>
</form>
</body>
</html>
页面对应的controller：
package botdetect.examples.springmvc.basic.controller;
import botdetect.examples.springmvc.basic.model.BasicExample;
import botdetect.web.Captcha;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.validation.BindException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.SimpleFormController;
public class IndexController extends SimpleFormController {
public IndexController(){
setCommandClass(BasicExample.class);
}
@Override
protected ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, Object command, BindException errors){
BasicExample basicExample = (BasicExample)command;
// validate the Captcha to check we‘re not dealing with a bot
Captcha captcha = Captcha.load(request, "basicExampleCaptcha");
boolean isHuman = captcha.validate(request,
basicExample.getCaptchaCodeTextBox());
if (isHuman) {
basicExample.setCaptchaCodeCorrect("Correct.");
basicExample.setCaptchaCodeIncorrect("");
} else {
basicExample.setCaptchaCodeCorrect("");
basicExample.setCaptchaCodeIncorrect("Incorrect!");
}
basicExample.setCaptchaCodeTextBox("");
return new ModelAndView("index", "basicExample", basicExample);
}
}
验证码对应的bean
package botdetect.examples.springmvc.basic.model;
public class BasicExample {
private String userCaptchaCode, captchaCodeCorrect, captchaCodeIncorrect;
public String getCaptchaCodeTextBox() {
return userCaptchaCode;
}
public void setCaptchaCodeTextBox(String userCaptchaCode) {
this.userCaptchaCode = userCaptchaCode;
}
public String getCaptchaCodeCorrect() {
return captchaCodeCorrect;
}
public void setCaptchaCodeCorrect(String captchaCodeCorrect) {
this.captchaCodeCorrect = captchaCodeCorrect;
}
public String getCaptchaCodeIncorrect() {
return captchaCodeIncorrect;
}
public void setCaptchaCodeIncorrect(String captchaCodeIncorrect) {
this.captchaCodeIncorrect = captchaCodeIncorrect;
}
}
下载验证码文件：
http://captcha.com/botdetect-java-captcha-component-free.zip
时间： 2024-10-13 22:33:23