很简陋的验证码学习

大体三步

1.创建验证码图片对象

BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

//2.美化图片  。。。。。

//3.把验证码图片输出到页面展示
ImageIO.write(image,"jpg",response.getOutputStream());
其对应的Servlet类为：

@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int width=100;
        int height=50;
        //1.创建验证码图片对象
        BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

        //2.美化图片
        Graphics g = image.getGraphics();
        g.setColor(Color.pink);
        g.fillRect(0,0,width,height);

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

        String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnoprstuvwxyz0123456789";
        Random random=new Random();

        for (int i=1;i<=4;i++){
            int index = random.nextInt(str.length());
            g.drawString(str.charAt(index)+"",i*width/5,height/2);
        }


        //画干扰线  5条
        g.setColor(Color.GREEN);
        for (int i = 0; i < 10; i++) {
            int x1 = random.nextInt(width);
            int x2 = random.nextInt(width);
            int y1 = random.nextInt(height);
            int y2 = random.nextInt(height);
            g.drawLine(x1,y1,x2,y2);
        }

        //3.把验证码图片输出到页面展示
        ImageIO.write(image,"jpg",response.getOutputStream());
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request,response);
    }
}
HTML页面

    
    

    


    
    
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