图片数字验证码生成

生成验证码

• controller层

@GetMapping("/image")
    public String image(HttpServletRequest request, HttpServletResponse response){
        RandomCodeTemp randomCodeTemp = new RandomCodeTemp();
        randomCodeTemp.getRandomCode(request,response);
        return String.valueOf(request.getSession());
    }

• 实现层

public class RandomCodeTemp {
    private Logger logger;
    /**
     * 图片流参数
     */
    // 放到session中的key
    public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY";
    // 随机产生数字和字母组合的字符串
    private String randString = "1234568789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    // 图片宽 越小图片文字越大(当stringNum超过5时， width就需要放大，否则可能出现显示不全问题,75对应 4和5位验证码，90对应6位验证码)
    private int width = 75;
    // 图片高 越小图片文字越大
    private int height = 20;
    // 干扰线的数量
    private int lineSize = 2;
    // 随机产生字符串的数量
    private int stringNum = 4;
    // 验证码背景RGB参数
    private Color backgroundColor = Color.white;
    // 验证码字体
    private Font font = new Font("Times New Roman", Font.ROMAN_BASELINE, 18);
    // 干扰线字体
    private Font drawFont = new Font("Fixedsys", Font.CENTER_BASELINE, 18);
    // 安全的随机数对象
    private SecureRandom random = new SecureRandom();

    /**
     * 获得干扰线字体
     * @return 干扰线字体
     */
    private Font getFont(){
        return drawFont;
    }
    /**
     * 获得颜色
     * @param fc
     * @param bc
     * @return
     */
    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);
    }
    /**
     * 绘制干扰线
     * @param g
     */
    private void drawLine(Graphics g){
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int x1 = random.nextInt(13);
        int y1 = random.nextInt(13);
        g.drawLine(x, y, x + x1,y + y1);
    }

    /**
     * 获取随机字符
     * @param num
     * @return
     */
    public String getRandomString(int num){
        return String.valueOf((randString.charAt(num)));
    }

    /**
     * 绘制字符串
     * @param g
     * @param randomString
     * @param i
     * @return
     */
    private String drawString(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(getRandomString(random.nextInt(randString.length())));
        randomString += rand;
        // 设置字符水平移动
        // g.translate(random.nextInt(3), random.nextInt(3));
        g.drawString(rand , 13 * i, 16);
        return randomString;
    }
    /**
     * 获得随机的字符
     * @param request
     * @param response
     */
    public void getRandomCode(HttpServletRequest request, HttpServletResponse response){
        HttpSession session = request.getSession();
        // BUfferedImage类是具有缓存区的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，该对象可以在图像上进行各种绘制操作
        Graphics g = image.getGraphics();
        // 设置背景透明
        g.setColor(backgroundColor);
        // 图片大小
        g.fillRect(0, 0, width, height = height);
        // 字体大小
        g.setFont(font);
        // 字体颜色
        g.setColor(getRandColor(110, 133));
        // 绘制干扰线
        // 判断是否需要干扰线
        if (lineSize > 0){
            for (int i=0; i<=lineSize; i++){
                drawLine(g);
            }
        }
        // 绘制随机的字符
        String randomString = "";
        for (int i = 0; i < stringNum; i++) {
            randomString = drawString(g, randomString, i);
        }
        // 将生成的随机字符串保存到session中
        session.removeAttribute(RANDOMCODEKEY);
        session.setAttribute(RANDOMCODEKEY, randomString);
        // 验证码图片布置生成
        g.dispose();
        try {
            ImageIO.write(image, "JPEG", response.getOutputStream());
        }catch (Exception e){
            logger.error("生成图片失效 ");
        }
    }
}