图片验证码

木瓜煲鸡脚

发布于 2019-08-20 14:34:28

2.1K0

发布于 2019-08-20 14:34:28

文章被收录于专栏：Jasper小笔记 Jasper小笔记Jasper小笔记

图片验证码

1.装有各种成语的文本文件

2.随机选取词语并绘制的servlet

3.页面静态文件html

4.判断验证码是否输入正确的servlet

words.txt

福如东海
寿比南山
马到成功
守株待兔
亡羊补牢

CheckWord.java

public class CheckWord extends HttpServlet {    private List<String> words = new ArrayList<String>();    @Override
    public void init() throws ServletException {        // 初始化阶段，读取new_words.txt
        // web工程中读取 文件，必须使用绝对磁盘路径
        String path = getServletContext().getRealPath("words.txt");        try {
            BufferedReader reader = new BufferedReader(new FileReader(path));
            String line;            while ((line = reader.readLine()) != null) {
                words.add(line);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {        // 禁止缓存
        // response.setHeader("Cache-Control", "no-cache");
        // response.setHeader("Pragma", "no-cache");
        // response.setDateHeader("Expires", -1);
        request.setCharacterEncoding("UTF-8");        int width = 120;        int height = 30;        // 步骤一 绘制一张内存中图片
        BufferedImage bufferedImage = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);        // 步骤二 图片绘制背景颜色 ---通过绘图对象
        Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔
        // 绘制任何图形之前 都必须指定一个颜色
        graphics.setColor(getRandColor(200, 250));
        graphics.fillRect(0, 0, width, height);        // 步骤三 绘制边框
        graphics.setColor(Color.WHITE);
        graphics.drawRect(0, 0, width - 1, height - 1);        // 步骤四 四个随机数字
        Graphics2D graphics2d = (Graphics2D) graphics;        // 设置输出字体
        graphics2d.setFont(new Font("宋体", Font.BOLD, 18));

        Random random = new Random();// 生成随机数
        int index = random.nextInt(words.size());
        String word = words.get(index);// 获得成语

        // 定义x坐标
        int x = 10;        for (int i = 0; i < word.length(); i++) {            // 随机颜色
            graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random
                    .nextInt(110), 20 + random.nextInt(110)));            // 旋转 -30 --- 30度
            int jiaodu = random.nextInt(60) - 30;            // 换算弧度
            double theta = jiaodu * Math.PI / 180;            // 获得字母数字
            char c = word.charAt(i);            // 将c 输出到图片
            graphics2d.rotate(theta, x, 20);
            graphics2d.drawString(String.valueOf(c), x, 20);
            graphics2d.rotate(-theta, x, 20);
            x += 30;
        }        // 将验证码内容保存session
        request.getSession().setAttribute("checkcode", word);        // 步骤五 绘制干扰线
        graphics.setColor(getRandColor(160, 200));        int x1;        int x2;        int y1;        int y2;        for (int i = 0; i < 30; i++) {
            x1 = random.nextInt(width);
            x2 = random.nextInt(12);
            y1 = random.nextInt(height);
            y2 = random.nextInt(12);
            graphics.drawLine(x1, y1, x1 + x2, x2 + y2);
        }        // 将上面图片输出到浏览器 ImageIO
        graphics.dispose();// 释放资源

        //将图片写到response.getOutputStream()中
        ImageIO.write(bufferedImage, "jpg", response.getOutputStream());

    }    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }    /**
     * 取其某一范围的color
     * 
     * @param fc
     *            int 范围参数1
     * @param bc
     *            int 范围参数2
     * @return Color
     */
    private Color getRandColor(int fc, int bc) {        // 取其随机颜色
        Random random = new Random();        if (fc > 255) {
            fc = 255;
        }        if (bc > 255) {
            bc = 255;
        }        int r = fc + random.nextInt(bc - fc);        int g = fc + random.nextInt(bc - fc);        int b = fc + random.nextInt(bc - fc);        return new Color(r, g, b);
    }

}

index.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<!--实现点击图片就再访问一次，并避免缓存问题-->
<script type="text/javascript">
    function freshen(obj){    
        obj.src="/check/CheckWord?time="+new Date().getTime();        
    }
</script>

</head>
<body>
<form action="/check/Judge">

        <img src="/check/CheckWord" onclick="freshen(this)"></br></br>
        <input type="text" name="inputWord" placeholder="请输入验证码"></br></br>
        <input type="submit" value="提交"> 
</form>
</body>
</html>

Judge.java

public class Judge extends HttpServlet {    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");

        String inputword= request.getParameter("inputWord");

        String checkword = (String) this.getServletContext().getAttribute("checkcode");        
        if(checkword.equals(inputword)) {
            response.getWriter().write("注册成功");
        }else {
            response.getWriter().write("验证码输入失败");
            response.setHeader("refresh", "2;url=/check");
        }

    }

}

演示