Java动态验证码生成
Keson Z 人气:0说明：今天给大家来带来一个自动生成验证码的处理方法。验证码的出现有效减少了注入灌水以及破解密码等恶意操作，提高了系统运行的流畅性，保护了系统用户的隐私安全，具体实现方法如下：
1.首先我们先编写一个专门的验证码生成工具类，该工具类代码如下：
package com.ordering.util;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;
/**
* 验证码生成器
* @author 诺坎普10号
* @date 2020-2-25
*/
public class CpachaUtil {
/**
* 验证码来源
*/
final private char[] code = {
'2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F',
'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R',
'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
};
/**
* 字体
*/
final private String[] fontNames = new String[]{
"黑体", "宋体", "Courier", "Arial",
"Verdana", "Times", "Tahoma", "Georgia"};
/**
* 字体样式
*/
final private int[] fontStyles = new int[]{
Font.BOLD, Font.ITALIC|Font.BOLD
};
/**
* 验证码长度
* 默认4个字符
*/
private int vcodeLen = 4;
/**
* 验证码图片字体大小
* 默认17
*/
private int fontsize = 21;
/**
* 验证码图片宽度
*/
private int width = (fontsize+1)*vcodeLen+10;
/**
* 验证码图片高度
*/
private int height = fontsize+12;
/**
* 干扰线条数
* 默认3条
*/
private int disturbline = 3;
public CpachaUtil(){}
/**
* 指定验证码长度
* @param vcodeLen 验证码长度
*/
public CpachaUtil(int vcodeLen) {
this.vcodeLen = vcodeLen;
this.width = (fontsize+1)*vcodeLen+10;
}
/**
* 指定验证码长度、图片宽度、高度
* @param vcodeLen
* @param width
* @param height
*/
public CpachaUtil(int vcodeLen,int width,int height) {
this.vcodeLen = vcodeLen;
this.width = width;
this.height = height;
}
/**
* 生成验证码图片
* @param vcode 要画的验证码
* @param drawline 是否画干扰线
* @return
*/
public BufferedImage generatorVCodeImage(String vcode, boolean drawline){
//创建验证码图片
BufferedImage vcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = vcodeImage.getGraphics();
//填充背景色
g.setColor(new Color(246, 240, 250));
g.fillRect(0, 0, width, height);
if(drawline){
drawDisturbLine(g);
}
//用于生成伪随机数
Random ran = new Random();
//在图片上画验证码
for(int i = 0;i < vcode.length();i++){
//设置字体
g.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)], fontsize));
//随机生成颜色
g.setColor(getRandomColor());
//画验证码
g.drawString(vcode.charAt(i)+"", i*fontsize+10, fontsize+5);
}
//释放此图形的上下文以及它使用的所有系统资源
g.dispose();
return vcodeImage;
}
/**
* 获得旋转字体的验证码图片
* @param vcode
* @param drawline 是否画干扰线
* @return
*/
public BufferedImage generatorRotateVCodeImage(String vcode, boolean drawline){
//创建验证码图片
BufferedImage rotateVcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = rotateVcodeImage.createGraphics();
//填充背景色
g2d.setColor(new Color(246, 240, 250));
g2d.fillRect(0, 0, width, height);
if(drawline){
drawDisturbLine(g2d);
}
//在图片上画验证码
for(int i = 0;i < vcode.length();i++){
BufferedImage rotateImage = getRotateImage(vcode.charAt(i));
g2d.drawImage(rotateImage, null, (int) (this.height * 0.7) * i, 0);
}
g2d.dispose();
return rotateVcodeImage;
}
/**
* 生成验证码
* @return 验证码
*/
public String generatorVCode(){
int len = code.length;
Random ran = new Random();
StringBuffer sb = new StringBuffer();
for(int i = 0;i < vcodeLen;i++){
int index = ran.nextInt(len);
sb.append(code[index]);
}
return sb.toString();
}
/**
* 为验证码图片画一些干扰线
* @param g
*/
private void drawDisturbLine(Graphics g){
Random ran = new Random();
for(int i = 0;i < disturbline;i++){
int x1 = ran.nextInt(width);
int y1 = ran.nextInt(height);
int x2 = ran.nextInt(width);
int y2 = ran.nextInt(height);
g.setColor(getRandomColor());
//画干扰线
g.drawLine(x1, y1, x2, y2);
}
}
/**
* 获取一张旋转的图片
* @param c 要画的字符
* @return
*/
private BufferedImage getRotateImage(char c){
BufferedImage rotateImage = new BufferedImage(height, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = rotateImage.createGraphics();
//设置透明度为0
g2d.setColor(new Color(255, 255, 255, 0));
g2d.fillRect(0, 0, height, height);
Random ran = new Random();
g2d.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)], fontsize));
g2d.setColor(getRandomColor());
double theta = getTheta();
//旋转图片
g2d.rotate(theta, height/2, height/2);
g2d.drawString(Character.toString(c), (height-fontsize)/2, fontsize+5);
g2d.dispose();
return rotateImage;
}
/**
* @return 返回一个随机颜色
*/
private Color getRandomColor(){
Random ran = new Random();
return new Color(ran.nextInt(220), ran.nextInt(220), ran.nextInt(220));
}
/**
* @return 角度
*/
private double getTheta(){
return ((int) (Math.random()*1000) % 2 == 0 ? -1 : 1)*Math.random();
}
/**
* @return 验证码字符个数
*/
public int getVcodeLen() {
return vcodeLen;
}
/**
* 设置验证码字符个数
* @param vcodeLen
*/
public void setVcodeLen(int vcodeLen) {
this.width = (fontsize+3)*vcodeLen+10;
this.vcodeLen = vcodeLen;
}
/**
* @return 字体大小
*/
public int getFontsize() {
return fontsize;
}
/**
* 设置字体大小
* @param fontsize
*/
public void setFontsize(int fontsize) {
this.width = (fontsize+3)*vcodeLen+10;
this.height = fontsize+15;
this.fontsize = fontsize;
}
/**
* @return 图片宽度
*/
public int getWidth() {
return width;
}
/**
* 设置图片宽度
* @param width
*/
public void setWidth(int width) {
this.width = width;
}
/**
* @return 图片高度
*/
public int getHeight() {
return height;
}
/**
* 设置图片高度
* @param height
*/
public void setHeight(int height) {
this.height = height;
}
/**
* @return 干扰线条数
*/
public int getDisturbline() {
return disturbline;
}
/**
* 设置干扰线条数
* @param disturbline
*/
public void setDisturbline(int disturbline) {
this.disturbline = disturbline;
}
}2.然后在页面端定义一个显示验证码的控件，再写一个js函数来对后台动态生成验证码方法进行调用，主要代码如下：
<div class="login-center-input-text">验证码</div>
<img id="cpacha-img" title="点击切换验证码" style="cursor:pointer;" src="get_cpacha?vl=4&w=150&h=40&type=loginCpacha" width="110px" height="30px" onclick="changeCpacha()">
</div>
<script type="text/javascript">
function changeCpacha(){
$("#cpacha-img").attr("src",'get_cpacha?vl=4&w=150&h=40&type=loginCpacha&t=' + new Date().getTime());
}
</script>3.控制器中代码如下：
/**
* 本系统所有的验证码均采用此方法
*
* @param vcodeLen
* @param width
* @param height
* @param cpachaType:用来区别验证码的类型，传入字符串
* @param request
* @param response
*/
@RequestMapping(value = "/get_cpacha", method = RequestMethod.GET)
public void generateCpacha(@RequestParam(name = "vl", required = false, defaultValue = "4") Integer vcodeLen,
@RequestParam(name = "w", required = false, defaultValue = "100") Integer width,
@RequestParam(name = "h", required = false, defaultValue = "30") Integer height,
@RequestParam(name = "type", required = true, defaultValue = "loginCpacha") String cpachaType,
HttpServletRequest request, HttpServletResponse response) {
//根据页面传入的验证码长度、图片宽度以及图片长度来实例化验证码实体
CpachaUtil cpachaUtil = new CpachaUtil(vcodeLen, width, height);
//生成验证码
String generatorVCode = cpachaUtil.generatorVCode();
//把验证码存入session
request.getSession().setAttribute(cpachaType, generatorVCode);
//根据验证码生成相应的验证码图片
BufferedImage generatorRotateVCodeImage = cpachaUtil.generatorRotateVCodeImage(generatorVCode, true);
try {
ImageIO.write(generatorRotateVCodeImage, "gif", response.getOutputStream());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}4.实现效果如下图所示：
5.控制器验证码验证部分如下图所示：
//若验证码为空
if (StringUtils.isEmpty(cpacha)) {
ret.put("type", "error");
ret.put("msg", "请填写验证码！");
return ret;
}
//获取保存在session中的登录验证码对象
Object loginCpacha = request.getSession().getAttribute("loginCpacha");
//若登录验证码实体对象为空
if (loginCpacha == null) {
ret.put("type", "error");
ret.put("msg", "会话超时，请刷新页面！");
return ret;
}
//若输入的验证码转化成大写之后不等于转换成大写的session中保存的验证码
if (!cpacha.toUpperCase().equals(loginCpacha.toString().toUpperCase())) {
ret.put("type", "error");
ret.put("msg", "验证码错误！");
//实例化日志信息实体
OrderingLog orderingLog = new OrderingLog("用户名为" + user.getOuUsername() + "的用户登录时输入验证码错误!", new Date());
//添加日志信息
logService.addLog(orderingLog);
return ret;
}注意：
只有当你把当前系统时间传入该验证码生成工具类中，才能实现点击验证码图片，实时自动替换验证码，如下图所示：
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