Kaptcha生成验证码

1.导入jar包 如kaptchar.2.3.jar
2.添加配置文件
Kaptcha生成验证码_第1张图片
Kaptcha生成验证码_第2张图片
3.使用方法`

function changeR(node){ // 用于点击时产生不同的验证码 node.src = "/randomcode.jpg?time="+new Date().getTime() ; }


random





获取验证码并校验

<body>
    <%
        // 检查是否是正确的验证码
        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>

4.说明
使用加法验证码需要注意(重写)



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(); //直接从验证码集合中选取四位,前两位作为加数1,后两位作为加数2 因此配置需要填写**4**位验证码 String s1 = capText.substring(0, 2); String s2 = capText.substring(2, 4);  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(); } } }

使用文字验证码直接修改文本集合即可,也可以重写类
如下` public String getText() {
int length = getConfig().getTextProducerCharLength();
//char[] charS = getConfig().getTextProducerCharString();

    String[] s = new String[]{"慕","课","网","教","程","验","证","码","实","例"};

    Random rand = new Random();
    StringBuffer sb = new StringBuffer();
    for(int i = 0; i < length; i++){
        int ind = rand.nextInt(s.length);
        sb.append(s[ind]);
    }
    return sb.toString();
}`

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