后端生成圖形驗證碼，并進行base64編碼生成字符串傳至前端，由前端解碼顯示圖形驗證碼，代碼如下：

后端-獲取圖形驗證碼base64編碼字符串接口：

/*** @param response* @return map* @throws Exception 獲取圖形驗證碼接口*/@RequestMapping("/getVerifyCode")@ResponseBodypublic Map getVerifyCode(HttpServletResponse response) throws Exception {Map map = new HashMap();//第一個參數是生成的驗證碼，第二個參數是生成的圖片Object[] objs = VerifyUtil.createImage();//將圖片輸出給瀏覽器BufferedImage image = (BufferedImage) objs[1];String value = objs[0].toString().toLowerCase();String key = UUID.randomUUID().toString();redisUtils.set(key, value, 2, MINUTES);ByteArrayOutputStream outputStream = new ByteArrayOutputStream();// 使用ServletOutputStream流可直接輸出圖片 // ServletOutputStream outputStream = response.getOutputStream();ImageIO.write(image, "png", outputStream);Base64 base64 = new Base64();String pic = new String(base64.encode(outputStream.toByteArray()));map.put("codeKey", key);map.put("codePic", pic);return map;}

后端-生成圖形驗證碼工具類

import java.awt.*; import java.awt.image.BufferedImage; import java.util.Random;/*** @param* @desc 圖形驗證碼生成**/ public class VerifyUtil {// 驗證碼字符集private static final char[] chars = {'1', '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'};// 字符數量private static final int SIZE = 4;// 干擾線數量private static final int LINES = 4;// 寬度private static final int WIDTH = 83;// 高度private static final int HEIGHT = 40;// 字體大小private static final int FONT_SIZE = 30;private static int[] w = {7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2};/*** 生成隨機驗證碼及圖片* Object[0]：驗證碼字符串；* Object[1]：驗證碼圖片。*/public static Object[] createImage() {StringBuffer sb = new StringBuffer();// 1.創建空白圖片BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);// 2.獲取圖片畫筆Graphics graphic = image.getGraphics();// 3.設置畫筆顏色graphic.setColor(Color.LIGHT_GRAY);// 4.繪制矩形背景graphic.fillRect(0, 0, WIDTH, HEIGHT);// 5.畫隨機字符Random ran = new Random();for (int i = 0; i <SIZE; i++) {// 取隨機字符索引int n = ran.nextInt(chars.length);// 設置隨機顏色graphic.setColor(getRandomColor());// 設置字體大小graphic.setFont(new Font(null, Font.BOLD + Font.ITALIC, FONT_SIZE));// 畫字符graphic.drawString(chars[n] + "", i * WIDTH / SIZE, HEIGHT*2/3);// 記錄字符sb.append(chars[n]);}// 6.畫干擾線for (int i = 0; i < LINES; i++) {// 設置隨機顏色graphic.setColor(getRandomColor());// 隨機畫線graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),ran.nextInt(WIDTH), ran.nextInt(HEIGHT));}// 7.返回驗證碼和圖片return new Object[]{sb.toString(), image};}/*** 隨機取色*/public static Color getRandomColor() {Random ran = new Random();Color color = new Color(ran.nextInt(256),ran.nextInt(256), ran.nextInt(256));return color;} }

前端-訪問獲取圖形驗證碼base64編碼字符串接口，并解碼顯示圖形驗證碼

<script src="/wjxcx/jquery.min.js"></script><img id="randomImage" title="點擊更換" id="imgcode" οnclick="javascript:refreshimg();" src="" /><script type="text/javascript">$(function(){refreshimg();})function refreshimg() {$.ajax({type : "post",dataType : "json",url : "/wjxcx/common/getKeyCode",data : {},success : function(data){$('#randomImage').attr('src', 'data:image/png;base64,'+data.codePic);},error : function(){}});} </script>

借鑒文章：
https://blog.csdn.net/fengbonu/article/details/78813094
https://blog.csdn.net/u010407050/article/details/52046820

可使用以下網站測試：
在線加密解密(采用Crypto-JS實現)：
http://tool.oschina.net/encrypt?type=4

總結

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