生成随机验证码工具类

1.生成验证码的工具类

public class ValidateCodeUtil{
    /**放到session中的key*/
    public static final String RANDOMCODEKEY= "RANDOMVALIDATECODEKEY";
    /**随机产生只有数字的字符串 private String*/
    //private String randString = "0123456789";
    /**随机产生只有字母的字符串*/
    //private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    /**随机产生数字与字母组合的字符串*/
    private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    /** 图片宽*/
    private int width = 115;
    /** 图片高*/
    private int height = 35;
    /**干扰线数量*/
    private int lineSize = 40;
    /**随机产生字符数量*/
    private int stringNum = 4;

    private static final Logger logger = LoggerFactory.getLogger(
            ValidateCodeUtil.class);

    private Random random = new Random();

    /**
     * 获得字体
     */
    private Font getFont() {
        return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
    }

    /**
     * 获得颜色
     */
    private Color getRandColor(int fc, int bc) {
        if (fc > 255)
        {fc = 255;}
        if (bc > 255)
        { bc = 255;}
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }

    /**
     * 生成随机图片
     */
    public void getRandcode(HttpServletRequest request, HttpServletResponse response) {
        HttpSession session = request.getSession();
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        // 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        Graphics g = image.getGraphics();
        //图片大小
        g.fillRect(0, 0, width, height);
        //字体大小
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
        //字体颜色
        g.setColor(getRandColor(110, 133));
        // 绘制干扰线
        for (int i = 0; i <= lineSize; i++) {
            drowLine(g);
        }
        // 绘制随机字符
        String randomString = "";
        for (int i = 1; i <= stringNum; i++) {
            randomString = drowString(g, randomString, i);
        }
        //将生成的随机字符串保存到session中
        session.removeAttribute(RANDOMCODEKEY);
        session.setAttribute(RANDOMCODEKEY, randomString);
        g.dispose();
        try {
            // 将内存中的图片通过流动形式输出到客户端
            ImageIO.write(image, "JPEG", response.getOutputStream());
        } catch (Exception e) {
            logger.error("将内存中的图片通过流动形式输出到客户端失败>>>>   ", e);
        }

    }

    /**
     * 绘制字符串
     */
    private String drowString(Graphics g, String randomString, int i) {
        g.setFont(getFont());
        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
                .nextInt(121)));
        String rand = String.valueOf(getImgCode(random.nextInt(randString
                .length())));
        randomString += rand;
        g.translate(random.nextInt(3), random.nextInt(3));
        g.drawString(rand, 13 * i, 16);
        return randomString;
    }

    /**
     * 绘制干扰线
     */
    private void drowLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x + xl, y + yl);
    }

    /**
     * 获取随机的字符
     */
    public String getImgCode(int num) {
        return String.valueOf(randString.charAt(num));
    }
}

2.Controller层调用

@org.springframework.stereotype.Controller
@RequestMapping("/code")
public class Controller{
    //org.slf4j.LoggerFactory
    private Logger log = LoggerFactory.getLogger(this.getClass());

    //    获取验证码
    @RequestMapping("/getVerify")
    public void getVerify(HttpServletRequest request, HttpServletResponse response) {
        try {
            //设置相应类型,告诉浏览器输出的内容为图片
            response.setContentType("image/jpeg");
            //设置响应头信息，告诉浏览器不要缓存此内容
            response.setHeader("Pragma", "No-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expire", 0);
            response.setCharacterEncoding("UTF-8");
            request.setCharacterEncoding("UTF-8");
            ValidateCodeUtil randomValidateCode = new ValidateCodeUtil();
            //输出验证码图片方法
            randomValidateCode.getRandcode(request, response);
        } catch (Exception e) {
            log.error("获取验证码失败>>>>   ", e);
        }
    }
}

3.调用

html:

 <a href="javascript:void(0);" title="点击更换验证码">
                            <img src="/code/getVerify" width="95%" class="imgcode"/>
                        </a>

js:

$('.imgcode').click(function() {
		var url =  "/code/getVerify?"+ Math.random();
		$(".imgcode").attr("src", url);
	});

效果如图：
http://localhost:8080/code/getVerify?0.3116131160655884