验证码生成与异步刷新

来源：互联网发布：java web开发环境编辑：程序博客网时间：2024/06/08 19:52

Spring mvc 部分代码

@RequestMapping(value = "/getAuthImg", method = RequestMethod.GET)@ResponseBodypublic void getAuthImg(HttpServletResponse response) throws IOException {new AuthImg().service(response);}

验证码生成代码 AuthImg.java ，将生成的验证码的码值放在了session中(这是shiro的部分代码，所以session获取是通过SecurityUtils.getSubject().getSession()得到的)

package com.util;import javax.servlet.http.*;import java.io.*;import java.awt.*;import java.awt.image.*;import java.util.*;import javax.imageio.*;import org.apache.shiro.SecurityUtils;public class AuthImg {//设置字体private final Font mFont = new Font("Arial Black", Font.PLAIN, 21);private final int IMG_WIDTH = 75;private final int IMG_HEIGTH = 36;public void service( HttpServletResponse response) throws IOException {response.setHeader("Pragma", "No-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);response.setContentType("image/jpeg");BufferedImage image = new BufferedImage(IMG_WIDTH, IMG_HEIGTH, BufferedImage.TYPE_INT_RGB);Graphics g = image.getGraphics();Random random = new Random();g.setColor(getRandColor(200, 250));g.fillRect(1, 1, IMG_WIDTH - 1, IMG_HEIGTH - 1);g.setColor(new Color(102, 102, 102));g.drawRect(0, 0, IMG_WIDTH - 1, IMG_HEIGTH - 1);g.setColor(getRandColor(160, 200));for (int i = 0; i < 30; i++) {int x = random.nextInt(IMG_WIDTH - 1);int y = random.nextInt(IMG_HEIGTH - 1);int xl = random.nextInt(6) + 1;int yl = random.nextInt(12) + 1;g.drawLine(x, y, x + xl, y + yl);}g.setColor(getRandColor(160, 200));for (int i = 0; i < 30; i++) {int x = random.nextInt(IMG_WIDTH - 1);int y = random.nextInt(IMG_HEIGTH - 1);int xl = random.nextInt(12) + 1;int yl = random.nextInt(6) + 1;g.drawLine(x, y, x - xl, y - yl);}g.setFont(mFont);String sRand = "";for (int i = 0; i < 4; i++) {String tmp = getRandomChar();sRand += tmp;g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));//设置字体位置g.drawString(tmp, 15 * i + 11, 25);}SecurityUtils.getSubject().getSession().setAttribute("rand", sRand);g.dispose();ImageIO.write(image, "JPEG", response.getOutputStream());}private String getRandomChar() {int rand = (int) Math.round(Math.random() * 2);long itmp = 0;char ctmp = '\u0000';switch (rand) {case 1:itmp = Math.round(Math.random() * 25 + 65);ctmp = (char) itmp;return String.valueOf(ctmp);case 2:itmp = Math.round(Math.random() * 25 + 97);ctmp = (char) itmp;return String.valueOf(ctmp);default:itmp = Math.round(Math.random() * 9);return itmp + "";}}private Color getRandColor(int fc, int bc) {Random random = new Random();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);}}

显示部分

<img src="getAuthImg" id="AuthImg">

js动态修改部分，防止浏览器缓存，加入一个时间属性

$('#AuthImg').on('click', function() {var timestamp = new Date().getTime();$(this).attr("src", $("#AuthImg").attr('src') + '?' + timestamp);});

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