Java swing生成图片验证码

 1 package com.donleo.ssm.common;
 2 
 3 
 4 import com.donleo.ssm.utils.CommonPath;
 5 import redis.clients.jedis.Jedis;
 6 
 7 import javax.imageio.ImageIO;
 8 import javax.servlet.ServletException;
 9 import javax.servlet.annotation.WebServlet;
10 import javax.servlet.http.HttpServlet;
11 import javax.servlet.http.HttpServletRequest;
12 import javax.servlet.http.HttpServletResponse;
13 import java.awt.*;
14 import java.awt.image.BufferedImage;
15 import java.io.IOException;
16 import java.io.OutputStream;
17 import java.util.Random;
18 
19 /**
20  * @author liangd
21  * date 2020-10-16 11:31
22  * code 生成验证码图片
23  */
24 @WebServlet("/code")
25 public class CodeServlet extends HttpServlet {
26     @Override
27     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
28         //创建空白图片
29         BufferedImage image = new BufferedImage(90, 30, BufferedImage.TYPE_INT_RGB);
30         //1.获取图片画笔
31         Graphics g = image.getGraphics();
32         Random r = new Random();//随机数
33 //        r.nextInt(255)，随机数在0到255之间 而且必须是整数
34         //2.设置画笔颜色
35 //        设置背景颜色，RGB 三个参数
36         g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255)));
37         //3. .绘制矩形的背景
38         g.fillRect(0, 0, 90, 30);
39 
40 
41         //4.调用自定义的方法,获取长度为5的字母数字组合的字符串
42         String number = getNumber(5);
43 //        System.out.println(number);
44         req.getSession().setAttribute("code", number);
45         Jedis jedis = new Jedis();
46         jedis.auth(CommonPath.REDIS_AUTH.getValue());
47         jedis.set("backCode",number);
48         g.setColor(new Color(0, 0, 0));
49         g.setFont(new Font("宋体", Font.BOLD, 24));
50         //5.设置颜色字体后，绘制字符串
51         g.drawString(number, 5, 25);
52         //6.绘制8条干扰线
53         for (int i = 0; i < 18; i++) {
54             g.setColor(new
55                     Color(r.nextInt(255), r.nextInt(255), r.nextInt(255), r.nextInt(255)));
56             g.drawLine(r.nextInt(90),
57                     r.nextInt(30),
58                     r.nextInt(90),
59                     r.nextInt(30));
60 //            直线参数 （a,b,x,y),a,b代表起点，x，y代表终点
61         }
62         resp.setContentType("image/ jpeg");
63         OutputStream ops = resp.getOutputStream();
64         ImageIO.write(image, "jpeg", ops);
65         ops.close();
66 
67     }
68 
69     /**
70      * 字符串的拼接
71      *
72      * @param size
73      * @return
74      */
75     private String getNumber(int size) {
76         //把I和O都去掉，因为和1,0不好识别
77         String str = "ASDFGHJKLQWERTYUIOPZXCVBNM";
78         StringBuilder number = new StringBuilder();
79         Random r = new Random();
80         for (int i = 0; i < size; i++) {
81             number.append(str.charAt(r.nextInt(str.length())));
82 //            str.charAt 拿到下标为0-str长度之间的下标，下标从0开始
83         }
84         return number.toString();
85     }
86 }