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使用java实现登录验证码(代码全)

程序员文章站 2022-04-16 15:02:16
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一、先写一个验证码工具类

package com.yx.cus.util;import java.awt.BasicStroke;import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;import java.util.Random;import javax.imageio.ImageIO;public class VerifyCode {
    private int w = 70;    private int h = 35;    private Random r = new Random();    // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"}
    private String[] fontNames  = {"宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312"};    private String codes  = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";    private Color bgColor  = new Color(255, 255, 255);    public static String text ;    private Color randomColor () {        int red = r.nextInt(150);        int green = r.nextInt(150);        int blue = r.nextInt(150);        return new Color(red, green, blue);
    }    private Font randomFont () {        int index = r.nextInt(fontNames.length);
        String fontName = fontNames[index];        int style = r.nextInt(4);        int size = r.nextInt(5) + 24; 
        return new Font(fontName, style, size);//指定字体名称、样式和点大小,创建一个新 Font。
    }    //画干扰的线条
    private void drawLine (BufferedImage image) {        int num  = 3;//画三条
        Graphics2D g2 = (Graphics2D)image.getGraphics();        for(int i = 0; i < num; i++) {            int x1 = r.nextInt(w);            int y1 = r.nextInt(h);            int x2 = r.nextInt(w);            int y2 = r.nextInt(h); 
            g2.setStroke(new BasicStroke(1.5F)); 
            g2.setColor(Color.BLUE); 
            g2.drawLine(x1, y1, x2, y2);
        }
    }    private char randomChar () {        int index = r.nextInt(codes.length());        return codes.charAt(index);
    }    private BufferedImage createImage () {
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 
        Graphics2D g2 = (Graphics2D)image.getGraphics(); 
        g2.setColor(this.bgColor);
        g2.fillRect(0, 0, w, h);        return image;
    }    public BufferedImage getImage () {
        BufferedImage image = createImage(); 
        Graphics2D g2 = (Graphics2D)image.getGraphics();
        StringBuilder sb = new StringBuilder();        // 向图片中画4个字符
        for(int i = 0; i < 4; i++)  {
            String s = randomChar() + ""; 
            sb.append(s); 
            float x = i * 1.0F * w / 4; 
            g2.setFont(randomFont()); 
            g2.setColor(randomColor()); 
            /**
             * 首字符的基线位于用户空间的 (x, h-5) 位置处
             * 原点在左上角,X轴递增的方向是从左向右;Y轴是从上到下
             * 在提供的坐标位于基线上最左边字符的情况下,可以从右到左呈现字形
             * h-5表示y轴方向,向上偏移了5
             */
            g2.drawString(s, x, h-5); 
        }        this.text = sb.toString(); 
        drawLine(image); 
        return image;       
    }    public String getText () {        return text;
    }    public static void output (BufferedImage image, OutputStream out) 
                throws IOException {
        ImageIO.write(image, "JPEG", out);
    }
}

这个工具类我们主要使用两个方法:
1.通过getImage()方法来制作验证码,返回BufferedImage 类型的验证码
2.通过getText()方法获取验证码的文本,返回String类型
二。验证码的接口(controller)

/**
 * 验证码
 * @param request
 * @return
 * @throws Exception 
 */@RequestMapping(value = "/VC", method = RequestMethod.POST)@ResponseBodypublic void  VC(HttpServletRequest request, HttpServletResponse response ) throws Exception{ 
   VerifyCode code=new VerifyCode();
   BufferedImage image = code.getImage();   //将验证码文本存到Redis
   vckey=IDUtil.nextId();
   JedisClient.set(vckey, code.getText(),60);
   ImageIO.write(image,"jpg",response.getOutputStream()); 
}

该接口会返回前端一个验证码,是以流的形式返回的,在返回之前会生成一个唯一的标识赋给一个全局变量,用来在redis里存入该验证码的文本,以作后用,存入的文本有时间限制
三、获取验证码文本标识的接口(就是存入验证码文本的值)

/**
 * 验证码文本的标识
 * @param request
 * @return
 * @throws Exception 
 */
   @RequestMapping(value = "/VCkey", method = RequestMethod.POST)@ResponseBodypublic String  VCkey(HttpServletRequest request, HttpServletResponse response ) throws Exception{ 
       System.out.println(vckey);   return vckey;
}

该接口主要就是把在redis里存验证码文本的键返回给前端,然后在登录的时候一起传回登录的接口
四、登录接口(试例)

String user_phone = reqstr.get("user_phone");//账号String user_pwd   = reqstr.get("user_pwd");//密码String vc   = reqstr.get("vc").toLowerCase();//用户输入的验证码String vckey   = reqstr.get("vckey");//前端获取的验证码文本的键(标识)String vcode= (String)JedisClient.get(vckey);//通过标识从redis里获取验证码文本if(vc.equals(vcode.toLowerCase())) {//用户输入的验证码与redsi存的作比较
   “验证码成功”
}else if(vcode==null){
    “验证码以过期”
}else{
     “验证码错误”
}

补充:验证码的键(标识)也可以在前端生成,比如生成一个时间戳,在请求验证码的接口时作为参数传入,这样后台就可以少写一个接口和全局变量

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