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java验证码生成与校验

2014-08-09 11:35 204 查看

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.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class RandomValidateCode {

public static final String RANDOM_VALIDATE_CODE = "RANDOM_VALIDATE_CODE";//放到session中的key
private Random random = new Random();
private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生的字符串

private int width = 80;//图片宽
private int height = 26;//图片高
private int lineSize = 40;//干扰线数量
private int stringNum = 4;//随机产生字符数量

// 生成随机图片
public void getRandCode(HttpServletRequest request, HttpServletResponse response) {
HttpSession session = request.getSession();
//BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
//产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
Graphics g = image.getGraphics();
g.fillRect(0, 0, width, height);
// 绘制前先设置字体，颜色
g.setFont(new Font("Times New Roman",Font.ROMAN_BASELINE,18));
g.setColor(getRandColor(110, 133));
//绘制干扰线
for(int i=0; i<=lineSize; i++){
drawLine(g);
}
//绘制随机字符
g.setFont(new Font("Fixedsys", Font.CENTER_BASELINE, 18));
StringBuilder sb = new StringBuilder();
// 每次随机画一个char
for(int i=1; i<=stringNum; i++){
String rand = String.valueOf(randString.charAt(random.nextInt(randString.length())));
g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
g.translate(random.nextInt(3), random.nextInt(3));
g.drawString(rand, 13*i, 16);
sb.append(rand);
}

session.removeAttribute(RANDOM_VALIDATE_CODE);
session.setAttribute(RANDOM_VALIDATE_CODE, sb.toString());
session.setAttribute("image", image);
System.out.println(sb);
g.dispose();
try {
ImageIO.write(image, "JPEG", response.getOutputStream());//将内存中的图片通过流动形式输出到客户端
} catch (Exception e) {
e.printStackTrace();
}
}

// 获得随机颜色
private Color getRandColor(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);
}

// 绘制干扰线
private void drawLine(Graphics g){
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(13);
int yl = random.nextInt(16);
g.drawLine(x, y, x+xl, y+yl);
}
}

@RequestMapping("refresh.html")
protected void refresh(HttpServletRequest request, HttpServletResponse response) {
response.setContentType("image/jpeg");// 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", 0);
RandomValidateCode randomValidateCode = new RandomValidateCode();
try {
randomValidateCode.getRandCode(request, response);// 输出图片方法
} catch (Exception e) {
e.printStackTrace();
}
}

@RequestMapping("validate.html")
@ResponseBody
protected String validate(HttpServletRequest request){
HttpSession session = request.getSession();
String code = (String) session.getAttribute(RandomValidateCode.RANDOM_VALIDATE_CODE);
String inputCode = request.getParameter("code");
if(code.equalsIgnoreCase(inputCode)){
return "success";
}else{
return "failure";
}
}

<!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=UTF-8">
<title></title>
</head>
<body>
<div align="center">
<div>
<form id="validateForm" action="validate.html">
<div>验证码：<input type="text" name="code"><img id="validationCode" title="点击更换" onclick="refresh(this);" src="refresh.html"></div>
<div><button type="button" onclick="doValidation();">提交</button></div>
</form>
</div>
</div>
</body>
<script type="text/javascript">
function refresh(obj){
// url变了，浏览器认为是访问了不同的图片路径，浏览器会每次重新访问服务器读取图片，而不再读取缓存中的图片
obj.src = "refresh.html?" + Math.random();
}

function doValidation(){
if(validateFormValidateor.form()){
$("#validateForm").ajaxSubmit({
success:function(data){
if(data == "success") {
alert("验证成功");
document.getElementById("validationCode").onclick();
}else{
alert("验证失败");
}
}
});
}
}

var validateFormValidateor;
$().ready(function(){
validateFormValidateor = $("#validateForm").validate({
rules:{
code:"required"
}
});
});
</script>
</html>

页面中图片的读取通过img中src属性，刷新图片通过修改url，添加随机参数

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