验证码与base64转换的工具类

谁践踏了优雅 2022-11-27 00:56 363阅读 0赞

### 验证码与base64转换的工具类 ###

*   *  1、关于验证码的工具类
     *  2、关于stringBase64与图像的互转
     *  3、验证码效果图

## 1、关于验证码的工具类 ##

package com.test.utils;
    
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.image.BufferedImage;
    import java.util.Random;
    
    /** * 验证码生成工具 */
    public class Captcha { 
        private BufferedImage image;// 图像
        private String captcha;// 验证码
        private static char code[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789".toCharArray();
    
        public static final String SESSION_CODE_NAME = "code";
    
        private Captcha() { 
            init();// 初始化属性
        }
    
        /* * 取得RandomNumUtil实例 */
        public static Captcha Instance() { 
            return new Captcha();
        }
    
        /* * 取得验证码图片 */
        public BufferedImage getImage() { 
            return this.image;
        }
    
        /* * 取得图片的验证码 */
        public String getString() { 
            return this.captcha;
        }
    
        private void init() { 
            // 在内存中创建图象
            int width = 170, height = 40;
            BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            // 获取图形上下文
            Graphics graphics = image.getGraphics();
            // 生成随机类
            Random random = new Random();
            // 设定背景色
            graphics.setColor(getRandColor(245, 250));
            graphics.fillRect(0, 0, width, height);
            // 设定字体
            graphics.setFont(new Font("Times New Roman", Font.PLAIN, 36));
    
            for (int i = 0; i < 500; i++) { 
                // 随机产生500条干扰线，使图象中的认证码不易被其它程序探测到
                graphics.setColor(getRandColor(150, 255));
                int x1 = random.nextInt(width);
                int y1 = random.nextInt(height);
                int x2 = random.nextInt(12);
                int y2 = random.nextInt(12);
                graphics.drawLine(x1, y1, x1 + x2, y1 + y2);
            }
            // 取随机产生的认证码(4位数字)
            String sRand = "";
            for (int i = 0; i < 4; i++) { 
                String rand = String.valueOf(code[random.nextInt(code.length)]);
                sRand += rand;
                // 将认证码显示到图象中
                graphics.setColor(new Color(1 + random.nextInt(255), 1 + random.nextInt(255), 1 + random.nextInt(255)));
                // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
                graphics.drawString(rand, 26 * i + 40, 32);
            }
            // 赋值验证码
            this.captcha = sRand;
            // 图象生效
            graphics.dispose();
            this.image = image;// 赋值图像
        }
    
        /* * 给定范围获得随机颜色 */
        private Color getRandColor(int start, int end) { 
            Random random = new Random();
            if (start > 255)
                start = 255;
            if (end > 255)
                end = 255;
            int r = start + random.nextInt(end - start);
            int g = start + random.nextInt(end - start);
            int b = start + random.nextInt(end - start);
            return new Color(r, g, b);
        }
    }

## 2、关于stringBase64与图像的互转 ##

package com.test.utils;
    
    import sun.misc.BASE64Decoder;
    
    import java.awt.*;
    import java.awt.image.BufferedImage;
    import java.awt.image.RenderedImage;
    import java.io.*;
    import java.nio.charset.StandardCharsets;
    import java.util.Base64;
    import javax.imageio.ImageIO;
    import javax.swing.*;
    
    public class Base64ToString { 
    
        //把图片转换成string类型
        public static String imgToBase64String(final RenderedImage img) { 
            final ByteArrayOutputStream os = new ByteArrayOutputStream();
            try { 
                ImageIO.write(img, "jpg", Base64.getEncoder().wrap(os));
                return os.toString(StandardCharsets.ISO_8859_1.name());
            } catch (final IOException ioe) { 
                throw new UncheckedIOException(ioe);
            }
        }
    
    
        //把string类型转换成图片
        public static BufferedImage base64StringToImg(final String base64String) { 
            try { 
                BASE64Decoder decoder = new BASE64Decoder();
                byte[] bytes = decoder.decodeBuffer(base64String);
                ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
                return ImageIO.read(bais);
            } catch (final IOException ioe) { 
                throw new UncheckedIOException(ioe);
            }
        }
    
    
        //绘制图片
        public static  void draw_image(BufferedImage image_buffer) throws IOException { 
            ImageIcon icon = new ImageIcon(image_buffer);
            JFrame frame = new JFrame();
            frame.setLayout(new FlowLayout());
    
            frame.setSize(image_buffer.getWidth(), image_buffer.getHeight());
            JLabel lbl = new JLabel();
            lbl.setIcon(icon);
            frame.add(lbl);
            frame.setVisible(true);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
        }
    
    }

## 3、验证码效果图 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUyMDY3MA_size_16_color_FFFFFF_t_70_pic_center]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUyMDY3MA_size_16_color_FFFFFF_t_70_pic_center]: /images/20221124/3581ab2dd6d24f6c9e3e447075ebf07b.png