前后端分离的图片验证保存及发送方式

1.如何保证同一浏览器保存的内容相同

请求图片验证码之前判断SessionStorage是否有KEY,如果没就创建，然后保存SessionStorage,如果有自己直接作为参数发送Ajax请求获取图片验证码

1. 前端通过ajax发送一个图片验证码请求,携带者KEY
2. 后端收到请求，生成图片验证码的值
3. 把图片验证码的值存储到Redis，以前段传入的key作为Redis的key
4. 把图片验证码的值合并到一个图片中
5. 把图片基于Base64编码层字符串，响应给前端
6. 前端拿到base64字符串，进行图片的展示，用户输入图片验证码
7. 前台提交注册请求 ，验证图片验证码(key也要携带)，后端把前端传入的图片验证码的值和Redis中的图片验证码的值做比

@Override
    public String imageCode(String key) {
        if(StringUtils.isEmpty(key)){
            throw new RuntimeException("验证码获取失败,请刷新页面重试");
        }
    //1.请求图片验证码之前判断SessionStorage是否有KEY,
    //        如果没就创建，然后保存SessionStorage,如果有自己直接作为参数发送Ajax请求获取图片验证码
    //2.前端通过ajax发送一个图片验证码请求,携带者KEY
    //3.后端收到请求，生成图片验证码的值
    //4.把图片验证码的值存储到Redis，以前段传入的key作为Redis的key
        //生成随机数
        String randomString = StrUtils.getComplexRandomString(4);
        try {
            String verifyCode = VerifyCodeUtils.VerifyCode(150, 50, randomString);
            AjaxResult setex = redisFegin.setex(key, 10000, randomString);
            if (!setex.isSuccess()){
                throw new RuntimeException("图片保存失败");
            }
            return verifyCode;
        } catch (IOException e) {
            throw new RuntimeException("图片保存Redis失败");
        }
    }

还有两个工具类

一个生成随机数

package cn.jiedada.hrm.util;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

/**
 * @author yaohuaipeng
 * @date 2018/10/26-16:16
 */
public class StrUtils {
    /**
     * 把逗号分隔的字符串转换字符串数组
     *
     * @param str
     * @return
     */
    public static String[] splitStr2StrArr(String str,String split) {
        if (str != null && !str.equals("")) {
            return str.split(split);
        }
        return null;
    }


    /**
     * 把逗号分隔字符串转换List的Long
     *
     * @param str
     * @return
     */
    public static List<Long> splitStr2LongArr(String str) {
        String[] strings = splitStr2StrArr(str,",");
        if (strings == null) return null;

        List<Long> result = new ArrayList<>();
        for (String string : strings) {
            result.add(Long.parseLong(string));
        }

        return result;
    }
    /**
     * 把逗号分隔字符串转换List的Long
     *
     * @param str
     * @return
     */
    public static List<Long> splitStr2LongArr(String str,String split) {
        String[] strings = splitStr2StrArr(str,split);
        if (strings == null) return null;

        List<Long> result = new ArrayList<>();
        for (String string : strings) {
            result.add(Long.parseLong(string));
        }

        return result;
    }

    public static String getRandomString(int length) {
        String str = "0123456789";
        Random random = new Random();
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < length; i++) {
            int number = random.nextInt(10);
            sb.append(str.charAt(number));
        }
        return sb.toString();

    }

    public static String getComplexRandomString(int length) {
        String str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        Random random = new Random();
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < length; i++) {
            int number = random.nextInt(62);
            sb.append(str.charAt(number));
        }
        return sb.toString();
    }

    public static String convertPropertiesToHtml(String properties){
        //1:容量:6:32GB_4:样式:12:塑料壳
        StringBuilder sBuilder = new StringBuilder();
        String[] propArr = properties.split("_");
        for (String props : propArr) {
            String[] valueArr = props.split(":");
            sBuilder.append(valueArr[1]).append(":").append(valueArr[3]).append("<br>");
        }
        return sBuilder.toString();
    }

}

 一个生成图片的工具类（这里也可以接入第三方）

前端不可以接收String转化为图片但可以通过base64的String转为图片，这里我们工具类里面就可以生成前端能够直接转化为图片的参数

package cn.jiedada.hrm.util;

import sun.misc.BASE64Encoder;
 
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Random;
 
/**
 * Created by Wzy
 * on 2018/5/11
 */
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
    public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    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();
    }
 
    /**
     * 输出指定验证码图片流
     *
     */
    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.ITALIC, 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);
            }
 
        }
 
    }
 
    /**
     * 获取随机验证码及其加密图片
     *  使用BASE64编码
     *  返回一个BASE64
     */
    public static String VerifyCode(int w, int h, int size) throws IOException {
        BASE64Encoder encoder = new BASE64Encoder();
        String code = generateVerifyCode(size).toLowerCase();
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        outputImage(w, h, data, code);
        return encoder.encode(data.toByteArray());
    }
    /**
     * 传入参数获得对应的图片验证
     *
     */
    public static String VerifyCode(int w, int h, String code) throws IOException {
        BASE64Encoder encoder = new BASE64Encoder();
        ByteArrayOutputStream data = new ByteArrayOutputStream();
        outputImage(w, h, data, code);
        return encoder.encode(data.toByteArray());
    }

    public static void main(String[] args) throws  Exception{
        System.out.println(VerifyCode(100, 30, 6));

    }
}