java生成验证码,可刷新
code.jsp
<%@ 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">
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %>
<%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic" %>
<%@ taglib uri="http://struts.apache.org/tags-tiles" prefix="tiles" %>
<html>
<head>
< http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>验证码</title>
</head>
<body>
<html:img page="/code.do" border="0" 这里写单击事件onclic k="this.src='/lookctrl/code.do'" alt="请输入此验证码，如看不清请点击刷新。" style="cursor:pointer" />
</body>
</html>
CodeAction.java
package struts.action;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.commons.lang.RandomStringUtils;
/**
* MyEclipse Struts Creation date: 08-2-2008
*
* XDoclet definition:
*
* @struts.action validate="true"
*/
public class CodeAction extends Action {
/*
* Generated Methods
*/
/**
* Method execute
*
* @param mapping
* @param form
* @param request
* @param response
* @return ActionForward
*/
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
try {
int width = 50;
int height = 18;
// 取得一个4位随机字母数字字符串
String s = RandomStringUtils.random(4, true, true);//这个s的值就是页面验证码上显示的值
// 保存入session,用于与用户的输入进行比较.
// 注意比较完之后清除session.
HttpSession session = request.getSession(true);
session.setAttribute("validateCode", s);
response.setContentType("images/jpeg");
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
ServletOutputStream out = response.getOutputStream();
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
// 设定背景色
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
// 设定字体
Font mFont = new Font("Times New Roman", Font.BOLD, 18);// 设置字体
g.setFont(mFont);
// 画边框
// g.setColor(Color.BLACK);
// g.drawRect(0, 0, width - 1, height - 1);
// 随机产生干扰线，使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160, 200));
// 生成随机类
Random random = new Random();
for (int i = 0; i < 155; i++) {
int x2 = random.nextInt(width);
int y2 = random.nextInt(height);
int x3 = random.nextInt(12);
int y3 = random.nextInt(12);
g.drawLine(x2, y2, x2 + x3, y2 + y3);
}
// 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(s, 2, 16);
// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write((BufferedImage) image, "JPEG", out);
out.close();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private 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);
}
}