图片验证码主要用于注册，登录等提交场景中，目的是防止脚本进行批量注册、登录、灌水，相比不带图片验证的安全度有所提高，不过目前也有自动识别图片验证码的程序出现，基本都是付费识别，随之又出现了滑动验证，选取正确选项验证等更加安全的验证方式。但图片验证码码仍用于大部分网站中。
一、前端图片验证码生成
前端逻辑大体就是进行图形绘制，取几个随机数放入图片中，加入干扰，进行验证
1.创建验证码组件identify.vue
<template>
<div class="s-canvas" style="display: inline">
<canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
</div>
</template>
<script>
export default{
name: 'SIdentify',
props: {
identifyCode: { // 默认注册码
type: String,
default: '1234'
},
fontSizeMin: { // 字体最小值
type: Number,
default: 25
},
fontSizeMax: { // 字体最大值
type: Number,
default: 35
},
backgroundColorMin: { // 验证码图片背景色最小值
type: Number,
default: 200
},
backgroundColorMax: { // 验证码图片背景色最大值
type: Number,
default: 220
},
dotColorMin: { // 背景干扰点最小值
type: Number,
default: 60
},
dotColorMax: { // 背景干扰点最大值
type: Number,
default: 120
},
contentWidth: { // 容器宽度
type: Number,
default: 117
},
contentHeight: { // 容器高度
type: Number,
default: 32
}
},
methods: {
// 生成一个随机数
randomNum (min, max) {
return Math.floor(Math.random() * (max - min) + min)
},
// 生成一个随机的颜色
randomColor (min, max) {
let r = this.randomNum(min, max)
let g = this.randomNum(min, max)
let b = this.randomNum(min, max)
return 'rgb(' + r + ',' + g + ',' + b + ')'
},
drawPic () {
let canvas = document.getElementById('s-canvas')
let ctx = canvas.getContext('2d')
ctx.textBaseline = 'bottom'
// 绘制背景
ctx.fillStyle = '#e6ecfd'
ctx.fillRect(0, 0, this.contentWidth, this.contentHeight)
// 绘制文字
for (let i = 0; i < this.identifyCode.length; i++) {
this.drawText(ctx, this.identifyCode[i], i)
}
this.drawLine(ctx)
this.drawDot(ctx)
},
drawText (ctx, txt, i) {
ctx.fillStyle = this.randomColor(50, 160) // 随机生成字体颜色
ctx.font = this.randomNum(this.fontSizeMin, this.fontSizeMax) + 'px SimHei' // 随机生成字体大小
let x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1))
let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5)
var deg = this.randomNum(-30, 30)
// 修改坐标原点和旋转角度
ctx.translate(x, y)
ctx.rotate(deg * Math.PI / 180)
ctx.fillText(txt, 0, 0)
// 恢复坐标原点和旋转角度
ctx.rotate(-deg * Math.PI / 180)
ctx.translate(-x, -y)
},
drawLine (ctx) {
// 绘制干扰线
for (let i = 0; i < 4; i++) {
ctx.strokeStyle = this.randomColor(100, 200)
ctx.beginPath()
ctx.moveTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight))
ctx.lineTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight))
ctx.stroke()
}
},
drawDot (ctx) {
// 绘制干扰点
for (let i = 0; i < 30; i++) {
ctx.fillStyle = this.randomColor(0, 255)
ctx.beginPath()
ctx.arc(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight), 1, 0, 2 * Math.PI)
ctx.fill()
}
}
},
watch: {
identifyCode () {
this.drawPic()
}
},
mounted () {
this.drawPic()
}
}
</script>2.父组件
前端生成验证码的校验是自己生成验证码，用户输入的值和生成的验证码字符串进行比对校验的，校验没有走后端，在真正发送请求到后端的时候也是不将验证码传给后台的。
<template>
<div slot="content" class="reg-body">
<div class="main-content">
<el-form ref="form" :model="form" :rules="rules" label-width="125px" label-position="left">
<el-form-item label="验证码" class="my-item" prop="code">
<el-input
v-model.trim="form.code"
placeholder="请输入正确的验证码"
size="small"
style="width: 200px "
/>
<span class="login-code" style="position: absolute; right: 0; top: 4px; left: 257px">
<Identify :identifyCode="identifyCode"></Identify>
</span>
<span
class="el-icon-refresh-right"
style="position: absolute; left: 394px; top: 13px; cursor: pointer"
@click="refreshCode"
/>
</el-form-item>
</el-form>
<div style="text-align: center">
<el-button
v-if="form.agreement"
style="background:#6BC6A1; color: white; border-radius:2px; width: 200px; height: 30px; line-height: 5px; border: none;margin-bottom: 10px"
@click="submitForm()"
:loading="loading"
>提交</el-button>
</div>
</div>
</div>
</template>
<script>
import Identify from "./identify";
export default {
name: "Reg",
mixins: [region],
components: {Identify },
data() {
return {
formSetting: {
contentWidth: 340,
},
form: {
logoUrl: "",
licenseUrl: "",
description: [],
account: "",
name: "",
},
code:this.$route.query.code,
identifyCodes: "1234567890abcdefjhijklinopqrsduvwxyz",
identifyCode: "",
picList: [],
props: { label: "name", value: "id", children: "children" },
rules: {
code: [{ required: true, message: "请输入验证码", trigger: "change" }],
},
formList: [],
};
},
created() {
// this.getAllDict()
},
mounted() {
this.getRegion();
// 初始化验证码
this.identifyCode = "";
this.makeCode(this.identifyCodes, 4);
localStorage.setItem("code", this.code);
},
methods: {
openHtml() {
this.visible = true;
},
//刷新验证码
refreshCode() {
this.identifyCode = "";
this.makeCode(this.identifyCodes, 4);
},
//生成验证上的随机数，验证码中的数从identifyCodes中取，
makeCode(o, l) {
for (let i = 0; i < l; i++) {
this.identifyCode += this.identifyCodes[
this.randomNum(0, this.identifyCodes.length)
];
}
},
//生成随机数,这里是生成
//Math.random()方法返回大于等于0小于1的一个随机数
//随机数 = Math.floor(Math.random() * 可能的总数 + 第一个可能的值)
randomNum(min, max) {
return Math.floor(Math.random() * (max - min) + min);
},
// 提交表单
submitForm() {
this.$refs["form"].validate((valid) => {
if (valid) {
if (this.loading) {
return;
}
this.loading = true;
this.submit();
} else {
return false;
}
});
},
submit: async function () {
if (this.form.code.toLowerCase() !== this.identifyCode.toLowerCase()) {
this.$msg({ type: "error", message: "请填写正确验证码" });
this.refreshCode();
this.loading = false;
return;
} else {
//验证码校验成功就可以调接口提交表单了
},
},
};
</script>二、后端生成图片验证码
后台思路很，利用BufferedImage类创建一张图片，再用Graphics对图片进行绘制(生成随机字符，添加噪点，干扰线)即可。
package com.hengtiansoft.gxrc.base.util;
import com.hengtiansoft.gxrc.common.constant.MagicNumConstant;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.imageio.ImageIO;
import java.awt.Font;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
@Slf4j
@Component
public class ImgCaptchaUtil {
private Random random = new Random();
private final int width = 160;
private final int height = 40;
private final int lineSize = 30;
private final String randomString = "0123456789abcdefghijklmnopqrstuvwxyz";
private Font getFont() {
return new Font("Times New Roman", Font.ROMAN_BASELINE, MagicNumConstant.FORTY);
}
private Color getRandomColor(int fc, int bc) {
int fcc = Math.min(fc, MagicNumConstant.TWO_HUNDRED_FIFTY_FIVE);
int bcc = Math.min(bc, MagicNumConstant.TWO_HUNDRED_FIFTY_FIVE);
int r = fcc + random.nextInt(bcc - fcc - MagicNumConstant.SIXTEEN);
int g = fcc + random.nextInt(bcc - fcc - MagicNumConstant.FOURTEEN);
int b = fcc + random.nextInt(bcc - fcc - MagicNumConstant.TWELVE);
return new Color(r, g, b);
}
private void drawLine(Graphics g) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(MagicNumConstant.TWENTY);
int yl = random.nextInt(MagicNumConstant.TEN);
g.drawLine(x, y, x + xl, y + yl);
}
private String getRandomString(int num) {
int number = num > 0 ? num : randomString.length();
return String.valueOf(randomString.charAt(random.nextInt(number)));
}
private String drawString(Graphics g, String randomStr, int i) {
g.setFont(getFont());
g.setColor(getRandomColor(MagicNumConstant.ONE_HUNDRED_EIGHT, MagicNumConstant.ONE_HUNDRED_NINETY));
String rand = getRandomString(random.nextInt(randomString.length()));
String randomString = randomStr + rand;
g.translate(random.nextInt(MagicNumConstant.THREE), random.nextInt(MagicNumConstant.SIX));
g.drawString(rand, MagicNumConstant.FORTY * i + MagicNumConstant.TEN, MagicNumConstant.TWENTY_FIVE);
return randomString;
}
public Map<String, String> getImgCodeBaseCode(int length) {
Map<String, String> result = new HashMap<>();
// 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);
Graphics g = image.getGraphics();
g.fillRect(0, 0, width, height);
// 获取颜色
g.setColor(getRandomColor(MagicNumConstant.ONE_HUNDRED_FIVE, MagicNumConstant.ONE_HUNDRED_EIGHTY_NINE));
// 获取字体
g.setFont(getFont());
// 绘制干扰线
for (int i = 0; i < lineSize; i++) {
drawLine(g);
}
// 绘制随机字符
String randomCode = "";
for (int i = 0; i < length; i++) {
randomCode = drawString(g, randomCode, i);
}
g.dispose();
result.put("imgCode", randomCode);
String base64Code = "";
try {
//返回 base64
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ImageIO.write(image, "PNG", bos);
byte[] bytes = bos.toByteArray();
Base64.Encoder encoder = Base64.getEncoder();
base64Code = encoder.encodeToString(bytes);
} catch (Exception e) {
log.debug(e.getMessage());
}
result.put("data", "data:image/png;base64," + base64Code);
return result;
}
}后台生成图片base64，和一个唯一的key（通过这个key判断是哪张图片），后台可以通过接口传给前端图片base64和key，前端输入验证码，传给后台key和验证码去校验验证。
package com.hengtiansoft.gxrc.base.service.impl;
import com.hengtiansoft.gxrc.base.service.ImgCaptchaService;
import com.hengtiansoft.gxrc.base.util.ImgCaptchaUtil;
import com.hengtiansoft.gxrc.common.constant.MagicNumConstant;
import com.hengtiansoft.gxrc.common.entity.exception.BusinessException;
import com.hengtiansoft.gxrc.common.redis.RedisOperation;
import com.hengtiansoft.gxrc.common.util.UUIDUtils;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import java.util.Map;
@Service
public class ImgCaptchaServiceImpl implements ImgCaptchaService {
private static final String IMG_CAPTCHA = "imgCaptcha:";
@Autowired
private RedisTemplate<String, Object> redisTemplate;
@Autowired
private ImgCaptchaUtil imgCaptchaUtil;
@Override
public Map<String, String> getImgCaptcha() {
RedisOperation redisOperation = new RedisOperation(redisTemplate);
Map<String, String> map = imgCaptchaUtil.getImgCodeBaseCode(MagicNumConstant.FOUR);
String uuid = UUIDUtils.createUUID();
redisOperation.set(IMG_CAPTCHA + uuid, map.get("imgCode"));
redisOperation.expire(IMG_CAPTCHA + uuid, MagicNumConstant.THIRTY_THOUSAND);
map.remove("imgCode");
map.put("key", uuid);
return map;
}
@Override
public void checkImgCaptcha(String code, String key) {
RedisOperation redisOperation = new RedisOperation(redisTemplate);
String captcha = redisOperation.get(IMG_CAPTCHA + key);
if (ObjectUtils.isEmpty(captcha) || !StringUtils.equals(captcha, code)) {
throw new BusinessException("验证码错误");
}
redisOperation.del(IMG_CAPTCHA + key);
}
}以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持编程网。
