您的位置：首页 > Web前端 > JavaScript

简单验证码实现（jsp）

2018-01-25 17:30 405 查看

页面code.jsp

<html>

<head>

<%!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);
}%>

<%
//设置页面不缓存

response.setHeader("Pragma", "No-cache");

response.setHeader("Cache-Control", "no-cache");

response.setDateHeader("Expires", 0);
// 在内存中创建图象

int width = 100, height = 35;

BufferedImage image = new BufferedImage(width, height,

BufferedImage.TYPE_INT_RGB);
// 获取图形上下文

Graphics g = image.getGraphics();
//生成随机类
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, 35));
//画边框 //g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);
// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
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);
}
// 取随机产生的认证码(4位数字)
String randString[] =
{
  "1","2","3","4","5",
  "6","7","8","9","0",

"a","b","c","e","f",
"g","h","i","j","k",
"l","m","n","o","p",
"q","r","s","t","u",
"v","w","x","y","z",

};
String sRand = "";

for (int i = 0; i < 4; i++) {
String rand = randString[random.nextInt(randString.length)];
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)));
//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
g.drawString(rand, 20 * i + 6, 28);
}
// 将认证码存入SESSION
session.setAttribute("rand", sRand);
// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write(image, "JPEG", response.getOutputStream());
out.clear();
out = pageContext.pushBody();

%>

<body>

</body>

</html>

使用
<img src="code.jsp" border="0" alt="验证码,看不清楚?请点击刷新验证码" onclick="this.src='code.jsp? ran='+Math.random()"
/>

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航