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基于struts的验证码实现

2010-10-27 09:16 218 查看

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产生4个验证码的ACTION：

————ValidateCodeAction.java————

package org.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;

public class ValidateCodeAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
try {
int width = 52;
int height = 22;
// 取得一个4位随机字母数字字符串
String code = RandomStringUtils.random(4, true, true);

// 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("code", code);

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(code, 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);
}

}

struts-config.xml中配置：

<action path="/ValidateCode" type="org.struts.action.ValidateCodeAction" />

JSP中调用的方法：

<html:img src="/ValidateCode.do" border="0"
onclick="this.src.value='/ValidateCode.do'"
alt="请输入此验证码，如看不清请点击刷新。" style="cursor: pointer"/>

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