jsp验证码

来源：互联网发布：php判断是否为全空格编辑：程序博客网时间：2024/05/07 08:39

常见的加减号验证码

<%@ page language="java" contentType="image/jpeg; charset=utf-8"

pageEncoding="utf-8"%>
<%@page import="java.awt.*,java.awt.image.*,javax.imageio.ImageIO,java.util.Random" %>
<%
int width = 100, height = 20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
Random random = new Random();
g.setColor(Color.WHITE);
g.fillRect(0, 0, width, height);
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
g.setColor(Color.BLACK);
int a = random.nextInt(10)+10;//可以选择其他
int b = random.nextInt(10);//同上
String[] opts = new String[]{"+","-"};//加减
String opt = opts[random.nextInt(2)];
int yanZhengMa = 0;// 四位随机数字码
if(opt.equals("+")){
yanZhengMa = a+b;
}else{
yanZhengMa = a-b;
}
g.drawString(a+"", 6, 16);
g.drawString(opt, 13*2 + 6, 16);
g.drawString(b+"", 13 * 3 + 6, 16);
g.drawString("=", 13 * 5 + 6, 16);
request.getSession().setAttribute("yanzhengma", yanZhengMa+"");
g.dispose();
ServletOutputStream os =response.getOutputStream();
ImageIO.write(image, "JPEG", os);
//防止报错
out.clear();
out = pageContext.pushBody();
%>