实现一个简单的登录验证码

实现原理

1.后台生成验证码传到页面
2.登录验证输入验证码是否正确

实现过程

1.引入一个生成验证码的工具类，网上很多 随便找一个根据需求改一下就可以

package com.utils;/*** ${DESCRIPTION}** @author * @create **/
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Random;import javax.imageio.ImageIO;public class VerifyCodeUtils{//使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符，以及占用太宽的字符Wpublic static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVXYZ";private static Random random = new Random();/*** 使用系统默认字符源生成验证码* @param verifySize    验证码长度* @return*/public static String generateVerifyCode(int verifySize){return generateVerifyCode(verifySize, VERIFY_CODES);}/*** 使用指定源生成验证码* @param verifySize    验证码长度* @param sources   验证码字符源* @return*/public static String generateVerifyCode(int verifySize, String sources){if(sources == null || sources.length() == 0){sources = VERIFY_CODES;}int codesLen = sources.length();Random rand = new Random(System.currentTimeMillis());StringBuilder verifyCode = new StringBuilder(verifySize);for(int i = 0; i < verifySize; i++){verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));}return verifyCode.toString();}/*** 生成随机验证码文件,并返回验证码值* @param w* @param h* @param outputFile* @param verifySize* @return* @throws IOException*/public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException{String verifyCode = generateVerifyCode(verifySize);outputImage(w, h, outputFile, verifyCode);return verifyCode;}/*** 输出随机验证码图片流,并返回验证码值* @param w* @param h* @param os* @param verifySize* @return* @throws IOException*/public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException{String verifyCode = generateVerifyCode(verifySize);outputImage(w, h, os, verifyCode);return verifyCode;}/*** 生成指定验证码图像文件* @param w* @param h* @param outputFile* @param code* @throws IOException*/public static void outputImage(int w, int h, File outputFile, String code) throws IOException{if(outputFile == null){return;}File dir = outputFile.getParentFile();if(!dir.exists()){dir.mkdirs();}try{outputFile.createNewFile();FileOutputStream fos = new FileOutputStream(outputFile);outputImage(w, h, fos, code);fos.close();} catch(IOException e){throw e;}}/*** 输出指定验证码图片流* @param w* @param h* @param os* @param code* @throws IOException*/public static void outputImage(int w, int h, OutputStream os, String code) throws IOException{int verifySize = code.length();BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);Random rand = new Random();Graphics2D g2 = image.createGraphics();g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);Color[] colors = new Color[5];Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,Color.PINK, Color.YELLOW };float[] fractions = new float[colors.length];for(int i = 0; i < colors.length; i++){colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];fractions[i] = rand.nextFloat();}Arrays.sort(fractions);g2.setColor(Color.GRAY);// 设置边框色g2.fillRect(0, 0, w, h);Color c = getRandColor(200, 250);g2.setColor(c);// 设置背景色g2.fillRect(0, 2, w, h-4);//绘制干扰线Random random = new Random();g2.setColor(getRandColor(160, 200));// 设置线条的颜色for (int i = 0; i < 20; i++) {int x = random.nextInt(w - 1);int y = random.nextInt(h - 1);int xl = random.nextInt(6) + 1;int yl = random.nextInt(12) + 1;g2.drawLine(x, y, x + xl + 40, y + yl + 20);}// 添加噪点float yawpRate = 0.05f;// 噪声率int area = (int) (yawpRate * w * h);for (int i = 0; i < area; i++) {int x = random.nextInt(w);int y = random.nextInt(h);int rgb = getRandomIntColor();image.setRGB(x, y, rgb);}shear(g2, w, h, c);// 使图片扭曲g2.setColor(getRandColor(100, 160));int fontSize = h-4;Font font = new Font("Algerian", Font.PLAIN, fontSize);g2.setFont(font);char[] chars = code.toCharArray();for(int i = 0; i < verifySize; i++){//AffineTransform affine = new AffineTransform();//affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2);//g2.setTransform(affine);g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h/2 + fontSize/2 - 10);}g2.dispose();ImageIO.write(image, "jpg", os);}private static Color getRandColor(int fc, int bc) {if (fc > 255)fc = 255;if (bc > 255)bc = 255;int r = fc + random.nextInt(bc - fc);int g = fc + random.nextInt(bc - fc);int b = fc + random.nextInt(bc - fc);return new Color(r, g, b);}private static int getRandomIntColor() {int[] rgb = getRandomRgb();int color = 0;for (int c : rgb) {color = color << 8;color = color | c;}return color;}private static int[] getRandomRgb() {int[] rgb = new int[3];for (int i = 0; i < 3; i++) {rgb[i] = random.nextInt(255);}return rgb;}private static void shear(Graphics g, int w1, int h1, Color color) {shearX(g, w1, h1, color);shearY(g, w1, h1, color);}private static void shearX(Graphics g, int w1, int h1, Color color) {int period = random.nextInt(2);boolean borderGap = true;int frames = 1;int phase = random.nextInt(2);for (int i = 0; i < h1; i++) {double d = (double) (period >> 1)* Math.sin((double) i / (double) period+ (6.2831853071795862D * (double) phase)/ (double) frames);g.copyArea(0, i, w1, 1, (int) d, 0);if (borderGap) {g.setColor(color);g.drawLine((int) d, i, 0, i);g.drawLine((int) d + w1, i, w1, i);}}}private static void shearY(Graphics g, int w1, int h1, Color color) {int period = random.nextInt(40) + 10; // 50;boolean borderGap = true;int frames = 20;int phase = 7;for (int i = 0; i < w1; i++) {double d = (double) (period >> 1)* Math.sin((double) i / (double) period+ (6.2831853071795862D * (double) phase)/ (double) frames);g.copyArea(i, 0, 1, h1, 0, (int) d);if (borderGap) {g.setColor(color);g.drawLine(i, (int) d, i, 0);g.drawLine(i, (int) d + h1, i, h1);}}}
}

2.controller中生成验证码并放入session

//生成图片验证码@GetMapping(value="verifyCode")public void verifyCode(Model model,HttpServletRequest request,HttpServletResponse response) {try {OutputStream outputStream=response.getOutputStream();int w = 200, h = 80;String code = VerifyCodeUtils.generateVerifyCode(4);request.getSession().setAttribute("securityCode", code);VerifyCodeUtils.outputImage(w, h, outputStream, code);outputStream.close();} catch (IOException e) {e.printStackTrace();}}

3.前端登录页面
只有主要代码，部分已经省略 

用户名：<input id="name" type="text">
密码：<input id="password" type="passwpord">
验证码：<input id="vercode"type="text">
<img src="${ctx}/home/verifyCode" title="看不清，点击刷新" onclick="reloadValidCode()" id="imgcode"/>

 JS（ajax）

//验证码刷新function reloadValidCode() {$("#imgcode").prop('src', "${ctx}/home/verifyCode?timed=" + new Date().getMilliseconds());}
//登录提交
$.ajax({url: "${ctx}/login",data: {'name': name,'password': password,'verificationCode':verificationCode},dataType: 'JSON',async: false,type: 'POST',success: function (data) {if (data.code == 200) {} else {errorAlert(data.msg)}}});	    

后端登录验证

@ResponseBody@PostMapping("/login")public JSONResponse loginValidate(@RequestParam(value = "realName") String realName,@RequestParam(value = "password") String password,@RequestParam(value = "verificationCode") String verificationCode){//登录验证（略）...String verCode = String.valueOf(request.getSession().getAttribute("securityCode"));verCode = verCode.toUpperCase();//判断图片验证码if (verCode.equals(verificationCode)){HttpSession session = request.getSession();return JSONResponseDiretor.buildSuccessJSONResponse(null);}return JSONResponseDiretor.buildErrorJSONResponse(ResponseEnum.LOGIN_VERIFICATIONCODE_ERROR, null);}}