JSP验证码生成 点击旋钮更新
日期：2014-05-16 浏览次数：20405 次
JSP验证码生成 点击按钮更新
ImageMaskServlet
点击“看不清换一张”
测试用例：
Index.jsp
<%@ page contentType="text/html; charset=utf-8" language="java"
import="java.util.*" errorPage=""%>
<HTML>
<head>
<title>测试</title>
</head>
<BODY id="body">
<form>
<img border=0 src="ImageMaskServlet" width="40" height="16" id = "imageMask">
<a href = "#" style = "font-size: 13px;margin-left: 5px;" onclick = "myReload()">看不清换一张</a>
</form>
<script type="text/javascript">
//用于刷新验证码
function myReload(){
document.getElementById("imageMask").src=document.getElementById("imageMask").src+"?nocache="+new Date().getTime();
}
</script>
</BODY>
</HTML>
ImageMaskServlet
package javaServlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
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 ImageMaskServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
int width = 60, height = 20;
//创建图象
BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);
//获取图形上下文
Graphics graphics = image.getGraphics();
//生成随机类
Random random = new Random();
//设定背景色
graphics.setColor(getRandColor(200, 250));
//验证码大小
graphics.fillRect(0, 0, width, height);
//设置字体
graphics.setFont(new Font("Times New Roman", Font.PLAIN, 18));
//graphics.setColor(getRandColor(160, 200));
//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
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);
graphics.drawLine(x, y, x + xl, y + yl);
}
//取随机产生的认证码(4位数字)
String sRand = "";
for (int i = 0; i < 4; i++) {
//0~9
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
//设置数字颜色
graphics.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
//把随机产生的4位数画在图片上
graphics.drawString(rand, 13 * i + 6, 16);
}
//放在session中
request.getSession().setAttribute("imageMask", sRand);
//图象生效
graphics.dispose();
//输出图象到页面
ImageIO.write(image, "JPEG", response.getOutputStream());
}
//生成随机颜色
public Color getRandColor(int fc, int bc) {
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);
}
}
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