Spring mvc实现验证码

1.验证码封装类

package com.huangqi.util;

import java.util.Random;
import java.awt.image.BufferedImage;
import java.awt.Graphics;
import java.awt.Font;
import java.awt.Color;

/**
* 验证码生成器类，可生成数字�?大写、小写字母及三�?混合类型的验证码�?支持自定义验证码字符数量�?支持自定义验证码图片的大小； 支持自定义需排除的特殊字符；
* 支持自定义干扰线的数量； 支持自定义验证码图文颜色
*/
public class ValidateCode {

/**
* 验证码类型为仅数�?0~9
*/
public static final int TYPE_NUM_ONLY = 0;

/**
* 验证码类型为仅字母，即大写�?小写字母混合
*/
public static final int TYPE_LETTER_ONLY = 1;

/**
* 验证码类型为数字、大写字母�?小写字母混合
*/
public static final int TYPE_ALL_MIXED = 2;

/**
* 验证码类型为数字、大写字母混�?
*/
public static final int TYPE_NUM_UPPER = 3;

/**
* 验证码类型为数字、小写字母混�?
*/
public static final int TYPE_NUM_LOWER = 4;

/**
* 验证码类型为仅大写字�?
*/
public static final int TYPE_UPPER_ONLY = 5;

/**
* 验证码类型为仅小写字�?
*/
public static final int TYPE_LOWER_ONLY = 6;

private ValidateCode() {

}

/**
* 生成验证码字符串
*
* @param type
*            验证码类型，参见本类的静态属�?
* @param length
*            验证码长度，大于0的整�?
* @param exChars
*            �?��除的特殊字符（仅对数字�?字母混合型验证码有效，无�?��除则为null�?
* @return 验证码字符串
*/
public static String generateTextCode(int type, int length, String exChars) {

if (length <= 0)
return "";

StringBuffer code = new StringBuffer();
int i = 0;
Random r = new Random();

switch (type) {

// 仅数�?
case TYPE_NUM_ONLY:
while (i < length) {
int t = r.nextInt(10);
if (exChars == null || exChars.indexOf(t + "") < 0) {// 排除特殊字符
code.append(t);
i++;
}
}
break;

// 仅字母（即大写字母�?小写字母混合�?
case TYPE_LETTER_ONLY:
while (i < length) {
int t = r.nextInt(123);
if ((t >= 97 || (t >= 65 && t <= 90)) && (exChars == null || exChars.indexOf((char) t) < 0)) {
code.append((char) t);
i++;
}
}
break;

// 数字、大写字母�?小写字母混合
case TYPE_ALL_MIXED:
while (i < length) {
int t = r.nextInt(123);
if ((t >= 97 || (t >= 65 && t <= 90) || (t >= 48 && t <= 57))
&& (exChars == null || exChars.indexOf((char) t) < 0)) {
code.append((char) t);
i++;
}
}
break;

// 数字、大写字母混�?
case TYPE_NUM_UPPER:
while (i < length) {
int t = r.nextInt(91);
if ((t >= 65 || (t >= 48 && t <= 57)) && (exChars == null || exChars.indexOf((char) t) < 0)) {
code.append((char) t);
i++;
}
}
break;

// 数字、小写字母混�?
case TYPE_NUM_LOWER:
while (i < length) {
int t = r.nextInt(123);
if ((t >= 97 || (t >= 48 && t <= 57)) && (exChars == null || exChars.indexOf((char) t) < 0)) {
code.append((char) t);
i++;
}
}
break;

// 仅大写字�?
case TYPE_UPPER_ONLY:
while (i < length) {
int t = r.nextInt(91);
if ((t >= 65) && (exChars == null || exChars.indexOf((char) t) < 0)) {
code.append((char) t);
i++;
}
}
break;

// 仅小写字�?
case TYPE_LOWER_ONLY:
while (i < length) {
int t = r.nextInt(123);
if ((t >= 97) && (exChars == null || exChars.indexOf((char) t) < 0)) {
code.append((char) t);
i++;
}
}
break;

}

return code.toString();
}

/**
* 已有验证码，生成验证码图�?
*
* @param textCode
*            文本验证�?
* @param width
*            图片宽度
* @param height
*            图片高度
* @param interLine
*            图片中干扰线的条�?
* @param randomLocation
*            每个字符的高低位置是否随�?
* @param backColor
*            图片颜色，若为null，则采用随机颜色
* @param foreColor
*            字体颜色，若为null，则采用随机颜色
* @param lineColor
*            干扰线颜色，若为null，则采用随机颜色
* @return 图片缓存对象
*/
public static BufferedImage generateImageCode(String textCode, int width, int height, int interLine,
boolean randomLocation, Color backColor, Color foreColor, Color lineColor) {

BufferedImage bim = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = bim.getGraphics();

// 画背景图
g.setColor(backColor == null ? getRandomColor() : backColor);
g.fillRect(0, 0, width, height);

// 画干扰线
Random r = new Random();
if (interLine > 0) {

int x = 0, y = 0, x1 = width, y1 = 0;
for (int i = 0; i < interLine; i++) {
g.setColor(lineColor == null ? getRandomColor() : lineColor);
y = r.nextInt(height);
y1 = r.nextInt(height);

g.drawLine(x, y, x1, y1);
}
}

// 写验证码

// g.setColor(getRandomColor());
// g.setColor(isSimpleColor?Color.BLACK:Color.WHITE);

// 字体大小为图片高度的80%
int fsize = (int) (height * 0.8);
int fx = height - fsize;
int fy = fsize;

g.setFont(new Font("Default", Font.PLAIN, fsize));

// 写验证码字符
for (int i = 0; i < textCode.length(); i++) {
fy = randomLocation ? (int) ((Math.random() * 0.3 + 0.6) * height) : fy;// 每个字符高低是否随机
g.setColor(foreColor == null ? getRandomColor() : foreColor);
g.drawString(textCode.charAt(i) + "", fx, fy);
fx += fsize * 0.9;
}

g.dispose();

return bim;
}

/**
* 生成图片验证�?
*
* @param type
*            验证码类型，参见本类的静态属�?
* @param length
*            验证码字符长度，大于0的整�?
* @param exChars
*            �?��除的特殊字符
* @param width
*            图片宽度
* @param height
*            图片高度
* @param interLine
*            图片中干扰线的条�?
* @param randomLocation
*            每个字符的高低位置是否随�?
* @param backColor
*            图片颜色，若为null，则采用随机颜色
* @param foreColor
*            字体颜色，若为null，则采用随机颜色
* @param lineColor
*            干扰线颜色，若为null，则采用随机颜色
* @return 图片缓存对象
*/
public static BufferedImage generateImageCode(int type, int length, String exChars, int width, int height,
int interLine, boolean randomLocation, Color backColor, Color foreColor, Color lineColor) {

String textCode = generateTextCode(type, length, exChars);
BufferedImage bim = generateImageCode(textCode, width, height, interLine, randomLocation, backColor, foreColor,
lineColor);

return bim;
}

/**
* 产生随机颜色
*
* @return
*/
private static Color getRandomColor() {
Random r = new Random();
Color c = new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255));
return c;
}

}

2.引用

/**
* 生成验证码
* @param request
* @param response
* @throws IOException
*/
@RequestMapping(value = "/validateCode")
public void validateCode(HttpServletRequest request, HttpServletResponse response) throws IOException {
response.setHeader("Cache-Control", "no-cache");//使用服务器端控制AJAX页面缓存
String verifyCode = ValidateCode.generateTextCode(ValidateCode.TYPE_NUM_ONLY, 4, null);
request.getSession().setAttribute("validateCode", verifyCode);
response.setContentType("image/jpeg");
BufferedImage bim = ValidateCode.generateImageCode(verifyCode, 90, 30, 3, true, Color.WHITE, Color.BLACK, null);
ImageIO.write(bim, "JPEG", response.getOutputStream());
}

3.jsp页面的引用

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>

<body>
<h1>login page</h1>
<form id="" action="dologin" method="post">
<label>User Name</label> <input tyep="text" name="userName"
maxLength="40" /> <label>Password</label><input type="password"
name="password" />
<li>验证码：<input type="text" name="validateCode" />  <img id="validateCodeImg" src="<%=basePath%>/validateCode" />  <a href="#" onclick="javascript:reloadValidateCode();">看不清？</a></li><input type="submit" value="login" />
</form>
<%--用于输入后台返回的验证错误信息 --%>
<P><c:out value="${message }" /></P>
</body>
<script src="js/jquery.min.js"></script>
<script type="text/javascript">
<!--
function reloadValidateCode(){
$("#validateCodeImg").attr("src","<%=basePath%>/validateCode?data=" + new Date() + Math.floor(Math.random()*24));
}
//-->
</script>
</html>