<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>checkcodes</title>
<script type="text/javascript">
<!--点击刷新-->
function code(obj){
obj.src="/WEB04/GenerateImageCodeServlet?time=1"+new Date().getTime();
}
</script>
</head>
<body>
<form action="<%=request.getContextPath()%>/login" method="get">
验证码：<input type="text" name="checkcode" />
<img alt="验证码" id="imagecode" src="/WEB04/GenerateImageCodeServlet" onclick="code(this)">
<a href="javascript:reloadCode();">看不清楚</a><br/>
<input type="submit" value="提交" />
<hr>
</form>
</body>
</html>
package com.colear.demo01;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.setContentType("text/html;charset=gbk");
String safeCode = (String) req.getSession().getAttribute("safeCode");
String checkcode = req.getParameter("checkcode");
PrintWriter out = resp.getWriter();
if (safeCode.equalsIgnoreCase(checkcode)) {
out.println("验证码正确");
}
else {
out.println("验证码错误");
}
out.flush();
out.close();
}
}
package com.colear.demo01;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Date;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class GenerateImageCodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final char[] CH = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890".toCharArray();
private static final int IMAGE_WIDTH = 73;
private static final int IMAGE_HEIGHT = 28;
private static final int LINE_NUM = 30;
private static final int RANDOM_NUM = 4;
Random random = new Random();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpg");//设置相应类型,告诉浏览器输出的内容为图片
response.setHeader("Pragma", "No-cache");//设置响应头信息，告诉浏览器不要缓存此内容
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expire", new Date().getTime());
BufferedImage bi = new BufferedImage(IMAGE_WIDTH, IMAGE_HEIGHT, BufferedImage.TYPE_INT_BGR);
Graphics g = bi.getGraphics();
g.fillRect(0, 0, IMAGE_WIDTH, IMAGE_HEIGHT);
g.setColor(getRandomColor(110, 133));
g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
// 绘制干扰线
for (int i = 1; i <= LINE_NUM; i++) {
int x = random.nextInt(IMAGE_WIDTH);
int y = random.nextInt(IMAGE_HEIGHT);
int xl = random.nextInt(13);
int yl = random.nextInt(15);
g.drawLine(x, y, x + xl, y + yl);
}
// 绘制随机字符
StringBuilder sb = new StringBuilder();
String str = null;
for (int i = 0; i < RANDOM_NUM; i++) {
g.setFont(new Font("Fixedsys", Font.CENTER_BASELINE, 18));
g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
str = CH[random.nextInt(CH.length)] + "";
g.drawString(str, 13 * i, 16);
g.translate(random.nextInt(3), random.nextInt(3));
sb.append(str);
}
g.dispose();
request.getSession().setAttribute("safeCode", sb.toString());
ImageIO.write(bi, "JPG", response.getOutputStream());
}
/**
* 获得颜色
*/
private Color getRandomColor(int fc, int bc) {
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
int r = fc + random.nextInt(bc - fc - 16);
int g = fc + random.nextInt(bc - fc - 14);
int b = fc + random.nextInt(bc - fc - 18);
return new Color(r, g, b);
}
}
