java实现简易的验证码功能

ResponseServlet.java:

@WebServlet("/responseServlet")
public class ResponseServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //创建图片对象
        int width = 100;
        int height= 50;
        BufferedImage image =new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

        //创建画笔对象
        Graphics g =image.getGraphics();

        //填充背景色
        g.setColor(Color.PINK);
        g.fillRect(0,0,width,height);

        //画边框
        g.setColor(Color.BLUE);
        g.drawRect(0,0,width-1,height-1);

        String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789";
        //生成随机角标
        Random ran = new Random();

        for (int i = 1; i <= 4; i++) {
            int index = ran.nextInt(str.length());
            //获取随机字符
            char ch = str.charAt(index);
            //写验证码
            g.drawString(ch+"",width/5*i,height/2);
        }


        //画干扰线
        g.setColor(Color.GREEN);
        //随机生成坐标点
        for (int i = 0; i < 10; i++) {
            int x1 = ran.nextInt(width);
            int x2 = ran.nextInt(width);
            int y1 = ran.nextInt(height);
            int y2 = ran.nextInt(height);
            g.drawLine(x1,y1,x2,y2);
        }

        //将图片写入resp
        ImageIO.write(image,"JPG",resp.getOutputStream());
    }
}

html写法：

<body>
<img id ="checkImage" src="/Response/responseServlet">
<a id="change" href="#">看不清，换一张</a>
</body>
<script>
    window.onload=function () {
        var checkImage = document.getElementById("checkImage");
        var change = document.getElementById("change");
        var check = function () {
            var time = new Date().getTime();
            checkImage.src = "/Response/responseServlet?"+time;
        };
        checkImage.onclick = check;
        change.onclick = check;
    }
</script>

效果图：

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原文链接：https://blog.csdn.net/qq_39369835/article/details/97394707
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发表于 2020-03-01 18:12:19
阅读 ( 985 )
分类：

java实现简易的验证码功能

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