Java实现图片验证码

• 1.创建工具类
• 2.调用工具类，返回验证码图片
• 3.效果

代码如下

//生成验证码，并将验证码存入session中，以ip为key
public class GetMessage {
    public static BufferedImage getMsg(HttpServletRequest request,String ip){
        int width = 60 , height = 30;
        //创建一个图像，宽60 高30
        BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandomColor(200,250));
        g.fillRect(0,0,width,height);
        g.setFont(new Font("Times New Roman",Font.PLAIN,18));
        g.setColor(getRandomColor(160,200));
        //干扰线生成
        for (int i = 0; i < 10; 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);
        }
        String strCode = "";
        for (int i = 0; i < 4; i++) {
            String strNumber = String.valueOf(random.nextInt(10));
            strCode = strCode+strNumber;
            //设置字体颜色
            g.drawString(strNumber,13*i+6,20);
        }
        System.out.println("当前ip"+ip);
        System.out.println("当前验证码"+strCode);
        request.getSession().setAttribute(ip,strCode);
        Common.setRedis(ip,strCode);
        g.dispose();
        return image;
    }


    
    public static Color getRandomColor (int fc , int bc){
        Random random = new Random();
        Color reandomColor = null;
        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);
        reandomColor = new Color(r,g,b);
        return reandomColor;
    }
}

代码如下：

    
    @PostMapping("getMessage")
    @ApiOperation(value = "获取图片验证码",notes = "获取图片验证码")
    @CrossOrigin
    public void getMessage(HttpServletResponse response, HttpServletRequest request){
        response.setHeader("Pragma","No-cache");
        response.setHeader("Cache-Control","No-cache");
        response.setDateHeader("Expires",0);
        response.setContentType("image/jpeg");
        String ip=request.getRemoteAddr();
        BufferedImage image= GetMessage.getMsg(request,ip);
        try {
            ImageIO.write(image,"JPEG",response.getOutputStream());
            response.getOutputStream().flush();
            response.getOutputStream().close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

上面代码调用工具类中的方法生成验证码图片，并将图片转换为数据流response返回给前端。

使用postman测试效果如下：