验证码生成工具

CaptchaUnit.java

package com.jason.www.common;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * @Project : medbook_hzwsj
 * @Package Name  : com.jason.www.common
 * @Description : 验证码生成工具
 * @Author : vlsion
 * @Creation Date : 2017/9/16 14:08
 * @ModificationHistory Who        When          What
 * --------   ----------    -----------------------------------
 */
public class CaptchaUtil {
    public static final String SESSION_CODE_NAME = "code";
    private static char code[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789".toCharArray();
    private BufferedImage image;// 图像
    private String str;// 验证码

    private CaptchaUtil() {
        init();// 初始化属性
    }

    /*
     * 取得RandomNumUtil实例
     */
    public static CaptchaUtil Instance() {
        return new CaptchaUtil();
    }

    /*
     * 取得验证码图片
     */
    public BufferedImage getImage() {
        return this.image;
    }

    /*
     * 取得图片的验证码
     */
    public String getString() {
        return this.str;
    }

    private void init() {
        // 在内存中创建图象
        int width = 85, height = 20;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 获取图形上下文
        Graphics g = image.getGraphics();
        // 生成随机类
        Random random = new Random();
        // 设定背景色
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        // 设定字体
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        // 取随机产生的认证码(4位数字)
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            String rand = String.valueOf(code[random.nextInt(code.length)]);
            sRand += rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(rand, 13 * i + 6, 16);
        }
        // 赋值验证码
        this.str = sRand;

        // 图象生效
        g.dispose();
        // ByteArrayInputStream input = null;
        // ByteArrayOutputStream output = new ByteArrayOutputStream();
        // try {
        // ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);
        // ImageIO.write(image, "JPEG", imageOut);
        // imageOut.close();
        // input = new ByteArrayInputStream(output.toByteArray());
        // } catch (Exception e) {
        // System.out.println("验证码图片产生出现错误：" + e.toString());
        // }
        // this.image = input
        this.image = image;/* 赋值图像 */
    }

    /*
     * 给定范围获得随机颜色
     */
    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);
    }
}

/**
 * 生成验证码
 *
 * @param request
 * @param response
 * @throws IOException
 */
@RequestMapping("/user/check.jpg")
public void createCode(HttpServletRequest request, HttpServletResponse response) throws IOException {
    // 通知浏览器不要缓存
    response.setHeader("Expires", "-1");
    response.setHeader("Cache-Control", "no-cache");
    response.setHeader("Pragma", "-1");
    CaptchaUtil util = CaptchaUtil.Instance();
    // 将验证码输入到session中，用来验证
    String code = util.getString();
    request.getSession().setAttribute("code", code);
    // 输出打web页面
    ImageIO.write(util.getImage(), "jpg", response.getOutputStream());
}


验证码所在位置

<div class="input_wrap"><input class="itext" name="code" placeholder="验证码"
                               style="width:138px;"/><img id="img"
                                                          src="user/check.jpg"
                                                          width="150"
                                                          height="37"
                                                          onclick="refresh()">
</div>

前台Js

<script type="text/javascript">

    function refresh() {
        var url = "user/check.jpg?number=" + Math.random();
        $("#img").attr("src", url);
    }
</script>