验证码java,验证码java使用random带学号

发布时间：2023-01-09

本文目录一览：

  1. 用java怎么制作验证码
  2. java如何实现发送短信验证码功能？
  3. Java如何实现验证码验证功能

用java怎么制作验证码

原理:

  1. 随机生成4个数字 用到了Random类
  2. 对这4个数字设置字体格式 用 setFont方法
  3. 改变字体颜色用setColor 然后随机生成颜色 代码如下
package s1;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.jms.Session;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class GetImage extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        this.doPost(request, response);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 发送图片不能够添加这2行代码
        // response.setContentType("text/html;charset=UTF-8");
        // request.setCharacterEncoding("UTF-8");
        int width = 100;
        int height = 50;
        // 获得一张图片
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        g.setColor(Color.WHITE);
        g.fillRect(1, 1, width - 2, height - 2);
        g.setFont(new Font("宋体", Font.BOLD, 30));
        Random random = new Random();
        // 填充的字符串
        String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        // 缓存生成的验证码
        StringBuffer stringbuffer = new StringBuffer();
        // 随机生成验证码的颜色和字符
        for (int i = 0; i < 4; i++) {
            // 设置随机颜色
            g.setColor(new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
            int index = random.nextInt(62); // 这里的62就是从填充字符段中随意选取一个位置
            String str1 = str.substring(index, index + 1);
            g.drawString(str1, 20 * i, 30); // x,y数值设置太小会显示不出来
            stringbuffer.append(str1);
        }
        // 将生成的验证码存到服务器
        request.getSession().setAttribute("checkcode", stringbuffer.toString()); // key和value
        // 将图片发送给浏览器
        ImageIO.write(image, "jpg", response.getOutputStream());
    }
}

用户登录界面代码

package s1;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class Login extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8"); // 设置服务器发送给浏览器的编码方式
        request.setCharacterEncoding("UTF-8"); // 客户端向服务器提交的数据的解码方式
        // 获得用户提交的数据
        String checkcode = request.getParameter("checkcode");
        System.out.println(checkcode);
        // 判断输入的验证码是不是符合
        HttpSession session = request.getSession(); // session是存放数据的地方
        String str = (String) session.getAttribute("checkcode");
        if (str != null) {
            if (checkcode.compareToIgnoreCase(str) == 0) // 验证码忽略大小写
                response.getWriter().println("验证码输入正确");
            else
                response.getWriter().println("验证码输入错误");
        } else
            response.getWriter().println("验证码失效");
        // 使用完的验证码信息要删除,返回原页面再输一次,验证码就失效了
        session.removeAttribute("checkcode");
    }
}

java如何实现发送短信验证码功能？

  1. 创建一个Http的模拟请求工具类，然后写一个POST方法或者GET方法
package com.demo.util;
import java.io.IOException;
import java.util.Map;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.SimpleHttpConnectionManager;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
public class HttpRequestUtil {
    public static String postRequest(String url, Map<String, String> params) {
        HttpClient httpClient = new HttpClient();
        PostMethod postMethod = new PostMethod(url);
        postMethod.setRequestHeader("Connection", "close");
        for (Map.Entry<String, String> entry : params.entrySet()) {
            postMethod.addParameter(entry.getKey(), entry.getValue());
        }
        httpClient.getParams().setBooleanParameter("http.protocol.expect-continue", false);
        String result = null;
        try {
            httpClient.executeMethod(postMethod);
            result = postMethod.getResponseBodyAsString();
        } catch (HttpException e) {
            System.out.println("请检查输入的URL!");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("发生网络异常!");
            e.printStackTrace();
        } finally {
            postMethod.releaseConnection();
            if (httpClient != null) {
                ((SimpleHttpConnectionManager) httpClient.getHttpConnectionManager()).shutdown();
                httpClient = null;
            }
        }
        return result;
    }
    public static String getRequest(String url, Map<String, String> params) {
        HttpClient client = new HttpClient();
        String paramStr = "";
        for (String key : params.keySet()) {
            paramStr = paramStr + "" + key + "=" + params.get(key);
        }
        paramStr = paramStr.substring(1);
        GetMethod method = new GetMethod(url + "?" + paramStr);
        String result = null;
        try {
            client.executeMethod(method);
            result = method.getResponseBodyAsString();
        } catch (HttpException e) {
            System.out.println("请检查输入的URL!");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("发生网络异常!");
            e.printStackTrace();
        } finally {
            method.releaseConnection();
            if (client != null) {
                ((SimpleHttpConnectionManager) client.getHttpConnectionManager()).shutdown();
                client = null;
            }
        }
        return result;
    }
}
  1. 在创建一个类，生成验证码，然后传递相应的参数（不同的短信平台接口会有不同的参数要求，这个一般短信平台提供的接口文档中都会有的，直接看文档然后按要求来即可）
package com.demo.util;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;
public class SendMsgUtil {
    @SuppressWarnings("deprecation")
    public static String sendMsg(String phones, String content) {
        String url = "短信接口URL提交地址";
        Map<String, String> params = new HashMap<>();
        params.put("zh", "用户账号");
        params.put("mm", "用户密码");
        params.put("dxlbid", "短信类别编号");
        params.put("extno", "扩展编号");
        params.put("hm", phones);
        params.put("nr", URLEncoder.encode(content));
        return HttpRequestUtil.getRequest(url, params);
    }
    public static String createRandomVcode() {
        String vcode = "";
        for (int i = 0; i < 6; i++) {
            vcode = vcode + (int) (Math.random() * 9);
        }
        return vcode;
    }
    public static void main(String[] args) {
        System.out.println(sendMsg("18123456789,15123456789", "尊敬的用户，您的验证码为" + SendMsgUtil.createRandomVcode()
                + "，有效期为60秒，如有疑虑请详询XXX-XXX-XXXX【XXX中心】"));
    }
}

然后执行一下，一般的情况下参数传递正确，按照接口文档的规范来操作的话，都会发送成功的，手机都能收到验证码的，然后可能会出现的问题就是：发送的短信内容有可能会出现中文乱码，然后就会发送不成功，按照短信平台的要求进行相应的编码即可。一般都会是UTF-8编码。

Java如何实现验证码验证功能

Java如何实现验证码验证功能呢？日常生活中，验证码随处可见，他可以在一定程度上保护账号安全，那么他是怎么实现的呢？ Java实现验证码验证功能其实非常简单：用到了一个Graphics类在画板上绘制字母，随机选取一定数量的字母随机生成，然后在画板上随机生成几条干扰线。 首先，写一个验证码生成帮助类，用来绘制随机字母：

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
public final class GraphicHelper {
    public static String create(final int width, final int height, final String imgType, OutputStream output) {
        StringBuffer sb = new StringBuffer();
        Random random = new Random();
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics graphic = image.getGraphics();
        graphic.setColor(Color.getColor("F8F8F8"));
        graphic.fillRect(0, 0, width, height);
        Color[] colors = new Color[] { Color.BLUE, Color.GRAY, Color.GREEN, Color.RED, Color.BLACK, Color.ORANGE,
                Color.CYAN };
        for (int i = 0; i < 50; i++) {
            graphic.setColor(colors[random.nextInt(colors.length)]);
            final int x = random.nextInt(width);
            final int y = random.nextInt(height);
            final int w = random.nextInt(20);
            final int h = random.nextInt(20);
            final int signA = random.nextBoolean() ? 1 : -1;
            final int signB = random.nextBoolean() ? 1 : -1;
            graphic.drawLine(x, y, x + w * signA, y + h * signB);
        }
        graphic.setFont(new Font("Comic Sans MS", Font.BOLD, 30));
        for (int i = 0; i < 6; i++) {
            final int temp = random.nextInt(26) + 97;
            String s = String.valueOf((char) temp);
            sb.append(s);
            graphic.setColor(colors[random.nextInt(colors.length)]);
            graphic.drawString(s, i * (width / 6), height - (height / 3));
        }
        graphic.dispose();
        try {
            ImageIO.write(image, imgType, output);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return sb.toString();
    }
}

接着，创建一个servlet，用来固定图片大小，以及处理验证码的使用场景，以及捕获页面生成的验证码（捕获到的二维码与用户输入的验证码一致才能通过）。

import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@WebServlet(urlPatterns = "/verify/regist.do")
public class VerifyCodeServlet extends HttpServlet {
    private static final long serialVersionUID = 3398560501558431737L;
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        HttpSession session = request.getSession();
        String uri = request.getRequestURI();
        System.out.println("hello : " + uri);
        final int width = 180; // 图片宽度
        final int height = 40; // 图片高度
        final String imgType = "jpeg"; // 指定图片格式 (不是指MIME类型)
        final OutputStream output = response.getOutputStream(); // 获得可以向客户端返回图片的输出流
        String code = GraphicHelper.create(width, height, imgType, output);
        System.out.println("验证码内容: " + code);
        session.setAttribute(uri, code);
        System.out.println(session.getAttribute(uri));
    }
}

接着写一个HTML注册页面用来检验一下：

<html>
<head>
    <meta charset="UTF-8">
    <title>注册</title>
    <link rel="stylesheet" href="styles/general.css">
    <link rel="stylesheet" href="styles/cell.css">
    <link rel="stylesheet" href="styles/form.css">
    <script type="text/javascript" src="js/ref.js"></script>
    <style type="text/css">
        .logo-container {
            margin-top: 50px;
        }
        .logo-container img {
            width: 100px;
        }
        .message-container {
            height: 80px;
        }
        .link-container {
            height: 40px;
            line-height: 40px;
        }
        .link-container a {
            text-decoration: none;
        }
    </style>
</head>
<body>
    <div class="container form-container">
        <form action="/wendao/regist.do" method="post">
            <div class="form"> <!-- 注册表单开始 -->
                <div class="form-row">
                    <span class="cell-1">
                        <i class="fa fa-user"></i>
                    </span>
                    <span class="cell-11" style="text-align: left;">
                        <input type="text" name="username" placeholder="请输入用户名">
                    </span>
                </div>
                <div class="form-row">
                    <span class="cell-1">
                        <i class="fa fa-key"></i>
                    </span>
                    <span class="cell-11" style="text-align: left;">
                        <input type="password" name="password" placeholder="请输入密码">
                    </span>
                </div>
                <div class="form-row">
                    <span class="cell-1">
                        <i class="fa fa-keyboard-o"></i>
                    </span>
                    <span class="cell-11" style="text-align: left;">
                        <input type="password" name="confirm" placeholder="请确认密码">
                    </span>
                </div>
                <div class="form-row">
                    <span class="cell-7">
                        <input type="text" name="verifyCode" placeholder="请输入验证码">
                    </span>
                    <span class="cell-5" style="text-align: center;">
                        <img src="/demo/verify/regist.do" onclick="myRefersh(this)">
                    </span>
                </div>
                <div class="form-row" style="border: none;">
                    <span class="cell-6" style="text-align: left">
                        <input type="reset" value="重置">
                    </span>
                    <span class="cell-6" style="text-align:right;">
                        <input type="submit" value="注册">
                    </span>
                </div>
            </div> <!-- 注册表单结束 -->
        </form>
    </div>
</body>
</html>

效果如下图： 在控制台接收到的图片中验证码的变化如下： 当点击刷新页面的时候，验证码也会随着变化，但我们看不清验证码时，只要点击验证码就会刷新，这样局部的刷新可以用JavaScript来实现。 在<img src="/demo/verify/regist.do"中，添加一个问号和一串后缀数字，当刷新时让后缀数字不断改变，那么形成的验证码也会不断变化，我们可以采用的一种办法是后缀数字用date代替，date获取本机时间，时间是随时变的，这样就保证了刷新验证码可以随时变化。 代码如下：

function myRefersh(e) {
    const source = e.src;
    var index = source.indexOf("?");
    if (index > -1) {
        var s = source.substring(0, index);
        var date = new Date();
        var time = date.getTime();
        e.src = s + "?time=" + time;
    } else {
        var date = new Date();
        e.src = source + "?time=" + date.getTime();
    }
}

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