验证码与base64转换的工具类-蒲公英云

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);
    }
}