使用java代码生成随机验证码

package com.xinrui.util;

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;

import org.springframework.stereotype.Component;

/**
*
* 创建时间：2016年2月21日 下午10:55:43 项目名称：SSI
*
* @author 梁志成
* @version 1.0
* @since JDK 1.8.0_21 文件名称：RandomValidateCode.java 类说明：生成图片验证码工具
*/
@Component
public class RandomValidateCode {
/**
* 生成代码
*
*/
public static String createValidateCode(int size) {
String seed = "1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM";
int len = seed.length();
char[] p = new char[size];
for (int i = 0; i < size; i++) {
p[i] = seed.charAt((int) Math.floor(Math.random() * len));
}
return new String(p);
}

private final Random random = new Random();
private final String randString = "123456789ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";// 随机产生的字符串
private final int width = 135;// 图片宽
private final int height = 33;// 图片高
private final int lineSize = 50;// 干扰线数量
private final int stringNum = 4;// 随机产生字符数量
private final int fontSize = 30;// 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(this.width, this.height,
BufferedImage.TYPE_INT_BGR);
Graphics g = image.getGraphics();// 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
g.fillRect(0, 0, this.width, this.height);
g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE,
this.fontSize));
g.setColor(this.getRandColor(110, 133));
// 绘制干扰线
for (int i = 0; i <= this.lineSize; i++) {
this.drawLine(g);
}
// 绘制随机字符
String randomString = "";
for (int i = 1; i <= this.stringNum; i++) {
randomString = this.drawString(g, randomString, i);
}
session.removeAttribute(Constants.RANDOM_CODE_KEY);
session.setAttribute(Constants.RANDOM_CODE_KEY, randomString);
// System.out.println(randomString);
g.dispose();
try {
// 禁止图像缓存。
response.setHeader("Pragma", "no-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
// 将内存中的图片通过流动形式输出到客户端
ImageIO.write(image, "JPEG", response.getOutputStream());
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* 获取随机的字符
*/
public String getRandomString(int num) {
return String.valueOf(this.randString.charAt(num));
}

/**
* 绘制干扰线
*/
private void drawLine(Graphics g) {
int x = this.random.nextInt(this.width);
int y = this.random.nextInt(this.height);
int xl = this.random.nextInt(13);
int yl = this.random.nextInt(15);
g.drawLine(x, y, x + xl, y + yl);
}

/**
* 绘制字符串
*/
private String drawString(Graphics g, String randomString, int i) {
g.setFont(this.getFont());
g.setColor(new Color(this.random.nextInt(155),
this.random.nextInt(123), this.random.nextInt(176)));
String rand = String.valueOf(this.getRandomString(this.random
.nextInt(this.randString.length())));
randomString += rand;
g.translate(this.random.nextInt(3), this.random.nextInt(3));
g.drawString(rand, (this.width / this.stringNum - 14) * i,
this.height - 7);
return randomString;
}

/**
* 获得字体
*/
private Font getFont() {
return new Font("Times New Roman", Font.CENTER_BASELINE, this.fontSize);
}

/**
* 获得颜色
*/
private Color getRandColor(int fc, int bc) {
if (fc > 255) {
fc = 255;
}
if (bc > 255) {
bc = 255;
}
int r = fc + this.random.nextInt(bc - fc - 16);
int g = fc + this.random.nextInt(bc - fc - 14);
int b = fc + this.random.nextInt(bc - fc - 18);
return new Color(r, g, b);
}
}

@RequestMapping(value = "vcode")
public void vcode(HttpServletRequest request, HttpServletResponse response) {
code.getRandcode(request, response);
}

<div class="tips">
<span>验证码
<input type="text" id="vcodetext">
<input id="vcode" type="image" src="vcode.html" onclick="changecode()"
style="position: absolute;">
</span>
</div>

/**
* 生成验证码
*/
var i = 1;
function changecode() {
$("#vcode").attr("src", "vcode.html?v=" + (i++));
}