验证码
求求大牛给一些产生登陆要正码的 方法及代码
[解决办法]
自己谷歌百度下不就有了。
[解决办法]
很简单的，你看看：<%@ page
import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"%>
<%@ page import="java.io.OutputStream"%>
<%@ page pageEncoding="UTF-8"%>
<%!Color getRandColor(int fc, int bc) {
//给定范围获得随机颜色
Random random = new Random();
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}%>
<%
try {
//设置页面不缓存
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Cache-Control", "no-store");
response.setDateHeader("Expires", 0);
// 在内存中创建图象
int width = 60, height = 20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
//返回客户端的输出流
OutputStream os = response.getOutputStream();
// 获取图形上下文
Graphics g = image.getGraphics();
//生成随机类对象
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
//设定字体
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
//随机生成155条干扰线
g.setColor(getRandColor(160, 200));
for (int i = 0; i < 155; i++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x, y, x + xl, y + yl);
}
//随机生成 Aa-Zz 0-9的4位验证码！
String sRand = "";
char[] str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
.toCharArray();
for (int i = 0; i < 4; i++) {
String rand = String.valueOf(str[random.nextInt(36)]);
sRand += rand;
// 将认证码显示到图象中
g.setColor(new Color(20 + random.nextInt(110), 20 + random
.nextInt(110), 20 + random.nextInt(110)));
g.drawString(rand, 13 * i + 6, 16);
}
// 将认证码存入SESSION
session.setAttribute("rand", sRand);
// 图象生效
g.dispose();
//输出图像到页面！
ImageIO.write(image, "JPEG", os);
os.flush();
os.close();
os = null;
response.flushBuffer();
out.clear();
out = pageContext.pushBody();
} catch (IllegalStateException e) {
System.out.println(e.getMessage());
e.printStackTrace();
}
%>
[解决办法]
最好后面再加上时间戳 ，(new Date()).getTime();
[解决办法]
网上有很多的，你去搜一下。
