JAVA生成网页图片验证码

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网页验证码总所周知，前言略，看效果图
这里写图片描述

用最简单的话，完成最快的工作

1. 生成验证码图片的类

import java.awt.*;import java.awt.image.BufferedImage;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * author : cnzxzc */public class RandomValidateCode {    private Random random = new Random();    private int width = 80;//图片宽    private int height = 26;//图片高    private int lineNum = 5;//干扰线数量    private int pointNum = 30;//噪点数量    private int stringNum = 4;//随机产生字符数量    private Font font = new Font("Times New Roman", Font.ROMAN_BASELINE, 18);    private char[] index = {'a','A','0'};//验证码索引    /**     * 生成验证码字符串     */    private char[] getValidateString(){        char[] c = new char[stringNum];        for(int i = 0; i<stringNum; i++) {            int offset = random.nextInt(3);            switch (offset) {                case 0:                case 1:                    c[i] = (char) ((int) index[offset] + random.nextInt(26));                    break;                case 2:                    c[i] = (char) ((int) index[offset] + random.nextInt(10));                    break;            }        }        return c;    }    /**     * 生成图片     * */    public void makeValidateImage(HttpServletRequest request, HttpServletResponse response){        //验证码        char[] text = getValidateString();        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);        Graphics2D g = image.createGraphics();        g.setFont(font);        g.setColor(Color.GREEN);        g.drawRect(0, 0, width, height);        g.setColor(Color.WHITE);        g.fillRect(0, 0, width, height);        //绘制干扰线        drowLine(g);        //绘制噪点        drowPoint(g);        //绘制随机字符        drowString(g, text);        try {            request.getSession().setAttribute("validateCode", new String(text));            ImageIO.write(image, "JPEG",  response.getOutputStream());        } catch (Exception e){            e.printStackTrace();        }finally {            g.dispose();        }    }    /**     * 绘制字符串     * */    private void drowString(Graphics g, char[] text){        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));        int x = random.nextInt(width);        int y = random.nextInt(height);        //防止画图画出范围        while(x>25){ x -= 20; }        while(y<13){ y += 10; }        g.drawChars(text, 0, stringNum, x, y);    }    /**     * 绘制干扰线     */    private void drowLine(Graphics g){        for(int i = 0; i < lineNum; i++) {            g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));            int x1 = random.nextInt(width);            int y1 = random.nextInt(height);            int x2 = random.nextInt(width);            int y2 = random.nextInt(height);            g.drawLine(x1, y1, x2, y2);        }    }    /**     * 绘制噪声点     */    private void drowPoint(Graphics g){        for(int i = 0; i < pointNum; i++) {            g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));            int x = random.nextInt(width);            int y = random.nextInt(height);            g.drawLine(x, y, x, y);        }    }}

2. Servlet文件有两个，一个用于启动，一个用于ajax校验

要是用struts或者Spring就不用两个文件这么麻烦了

//用于启动的servletprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        RandomValidateCode r = new RandomValidateCode();        r.makeValidateImage(request, response);    }

//用于校验的Servletprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        String validateCode = (String) (request.getSession().getAttribute("validateCode"));        response.getWriter().write(validateCode);    }

3. 页面代码( jsp )

<%@ page contentType="text/html;charset=UTF-8" language="java" %><html>  <head>    <title>sy6</title>    <script type="text/javascript" src="http://static.hdslb.com/js/jquery.min.js"></script>    <script type="text/javascript">      function check(code){        $.ajax({          type:"post",          url:"${pageContext.request.contextPath}/CheckServlet",          data: "code=" + code,          success:function(data){            if(data!=code) {              document.getElementById("mes").innerHTML = "<p style='color: red;'>错误</p>";            } else document.getElementById("mes").innerHTML = "<p style='color: GREEN;'>√</p>";          }        });      }    </script>    <style type="text/css">      #main{        width:540px;        padding:10px;        margin:250px auto;        text-align:center;        border-radius:5px;        box-shadow:-2px 0 10px #ccc,2px 0 10px #ccc;      }      #main button{        width: 70px;        height: 50px;        font-size: 16px;        color: white;        background-color: dodgerblue;        border: none;        border-radius: 10px;        box-shadow:-2px 0 10px #ccc,2px 0 10px #ccc;      }    </style>  </head>  <body>    <div id="main">      <form action="${pageContext.request.contextPath}/ForwardServlet" id="form">        <img id="validate" src="${pageContext.request.contextPath}/ValidateServlet">        <input type="text" name="key" onchange="check(this.value)"><div id="mes"></div><br>        <input type="submit">      </form>    </div>  </body></html>

效果如开头的图所示

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