图片验证码图片格式返回

最新推荐文章于 2020-09-30 11:31:28 发布

huochaiyiersan

最新推荐文章于 2020-09-30 11:31:28 发布

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本文详细介绍了如何在后端生成并发送验证码至前端的过程。通过使用随机数和颜色，生成了包含字母和数字的验证码图片，并将其存储在session中以供后续验证。前端通过GET请求并携带随机数参数获取验证码，同时提供了刷新验证码的功能。

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@RequestMapping(value="/getgradecode_bak")
public void getGradeCode_bak(HttpServletRequest request, HttpServletResponse response) throws  Exception{
    HttpSession session = request.getSession();
    int width = 80;
    int height =24;
    Random random = new Random();
    //设置response头信息
    //禁止缓存
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);

    //生成缓冲区image类
    BufferedImage image = new BufferedImage(width, height, 1);
    //产生image类的Graphics用于绘制操作
    Graphics g = image.getGraphics();
    //Graphics类的样式
    //设置背景颜色
     g.setColor(Color.GRAY);
    //g.setColor(this.getRandColor(200, 250));
    g.setFont(new Font("Times New Roman",0,22));
    g.fillRect(0, 0, width, height);
    String[] str = new String[] { "0","1","2", "3", "4", "5", "6", "7",
            "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J",
            "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",
            "W", "X", "Y", "Z", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j",
            "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
            "w", "x", "y", "z" };
    //绘制字符
    String verifyCode = "";
    for (int i = 0; i < 4; i++) {
        int number = random.nextInt(62);;
        String rand=str[number];
        verifyCode = verifyCode + rand;
        //设置字体颜色
        g.setColor(Color.white);
        //g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
        g.drawString(rand, 13*i+6, 22);
    }
    //将字符保存到session中用于验证
    session.removeAttribute(ASMALLConstant.SESSION_WX_VERIFY_CODE);
    session.setAttribute(ASMALLConstant.SESSION_WX_VERIFY_CODE, verifyCode);
    Log.info(this.getClass(),"此次动态验证码"+verifyCode);
    g.dispose();
    response.setHeader("content-type","image/gif");
    ImageIO.write(image, "JPEG", response.getOutputStream());
    response.getOutputStream().flush();
    response.getOutputStream().close();

}


//创建颜色，创建彩色版本备用代码
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);
}

2、前端请求使用get，带一个sui随机数请求

127.0.0.1:8086/web名?a=sui'随机数

htm中的代码