Kaptcha生成验证码

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1.导入jar包如kaptchar.2.3.jar
2.添加配置文件
这里写图片描述

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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