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W
public 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();
<
4000
span class="token punctuation">}

/**
* 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);
}
}

以上均是主要代码，部分可能需要自己修改，希望对您有用~若有错误或者更好的建议，欢迎提出！