標籤：color java io for ar html new htm
在JSP頁面上寫隨機的4位元驗證碼
執行個體化BufferedImage類 得到Graphics畫筆給圖片填充背景色 然後寫上隨機數和100個幹擾點
用scropt實現重新整理驗證碼
疑問：視頻和書上的DrawString 方法不能用 也不知道怎麼回事 把String轉成了char調用了另外一個drawChars的方法才對
<%@ page language="java" contentType="text/html; charset=GB2312"import = "java.awt.image.*"import = "java.util.*"import = "java.awt.*"import = "javax.imageio.*"import = "java.lang.*"%><html><head></head><body><% 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()); %></body></html>
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