JSP Verification Code

JSP Verification Code

Write a random 4-digit verification code on the JSP page

Instantiate the BufferedImage class to get the Graphics paint brush to fill the image with the background color and then write a random number and 100 interference points.

Use scropt to refresh the verification code

Question: the DrawString method in videos and books cannot be used and I don't know what's going on. Convert String to char and call another drawChars method.

<%@ page language="java" contentType="text/html; charset=GB2312"import = "java.awt.image.*"import = "java.util.*"import = "java.awt.*"import = "javax.imageio.*"import = "java.lang.*"%><% response.setHeader("Cache-Control", "no-cache");BufferedImage image = new BufferedImage(60, 20, BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); g.setColor(new Color(200, 200, 200));g.fillRect(0, 0, 60, 20);Random rd = new Random(); int r = rd.nextInt(8999) + 1000; String rand = String.valueOf(r); session.setAttribute("rand", rand); g.setColor(Color.BLACK); g.setFont(new Font("", Font.PLAIN, 20)); g.drawChars(rand.toCharArray(), 0, rand.length(), 10, 17); for(int i = 0; i < 100; i++){ int x = rd.nextInt(60); int y = rd.nextInt(20); g.drawOval(x, y, 1, 1); } ImageIO.write(image, "JPEG", response.getOutputStream()); %>