Java生成base64文字图

心已赠人 2024-03-16 15:10 7阅读 0赞

## Java生成base64文字图 ##

### 什么是文字图 ###

文字图是一种特别小的图片，图片内容是1-2个文字，常用来做默认头像默认Logo之类的图片。
    前端展示文字图，可以直接用img标签的base64图片功能来展示，也可以要求后端提供存好的图片的url，
    由于文字图非常小，建议直接给前端提供文字图的base64字符串，为后端节省存储压力

### Java生成文字图的自定义工具类 ###

package cn.ath.knowwikibackend.util;
    
    
    import cn.hutool.core.img.ImgUtil;
    import cn.hutool.core.io.FileUtil;
    import cn.hutool.core.util.RandomUtil;
    import cn.hutool.core.util.StrUtil;
    
    import javax.imageio.ImageIO;
    import java.awt.*;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.IOException;
    import java.util.regex.Matcher;
    import java.util.regex.Pattern;
    
    public class AvatarBuildUtil {
        
    
        /**
         * 获取1个随机的rgb颜色，转为java.awtColor
         * @return Color
         */
        private static Color getRandomColor() {
        
            String[] beautifulColors =
                    new String[]{
        "114,101,230", "255,191,0", "0,162,174", "245,106,0", "24,144,255", "96,109,128"};
            String[] color = beautifulColors[RandomUtil.randomInt(beautifulColors.length)].split(StrUtil.COMMA);
            return new Color(Integer.parseInt(color[0]), Integer.parseInt(color[1]),
                    Integer.parseInt(color[2]));
        }
    
    
        /**
         * 判断输入的是不是中文名
         * @param str String
         * @return boolean
         */
        private static boolean isChinese(String str) {
        
            String regEx = "[\\u4e00-\\u9fa5]+";
            Pattern p = Pattern.compile(regEx);
            Matcher m = p.matcher(str);
            return m.find();
        }
    
        /**
         * 用BufferedImage构建文字图
         * @param name String
         * @return BufferedImage
         */
        private static BufferedImage generateWZTBufferedImage(String name){
        
            int width = 100;
            int height = 100;
            int nameLength = name.length();
            String nameWritten;
            // 如果用户输入的姓名少于等于2个字符，不用截取
            if (nameLength <= 2) {
        
                nameWritten = name;
            } else {
        
                // 如果用户输入的姓名大于等于3个字符，截取后面两位
                String first = StrUtil.sub(name, 0, 1);
                if (isChinese(first)) {
        
                    // 截取倒数两位汉字
                    nameWritten = name.substring(nameLength - 2);
                } else {
        
                    // 截取前面的两个英文字母
                    nameWritten = StrUtil.sub(name, 0, 1).toUpperCase();
                }
            }
            BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics2D g2 = (Graphics2D) bufferedImage.getGraphics();
            g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
            g2.setBackground(getRandomColor());
            g2.clearRect(0, 0, width, height);
            g2.setPaint(Color.WHITE);
            Font font;
            // 两个字及以上
            if(nameWritten.length() >= 2) {
        
                font = new Font("微软雅黑", Font.BOLD, 30);
                g2.setFont(font);
                String firstWritten = StrUtil.sub(nameWritten, 0, 1);
                String secondWritten = StrUtil.sub(nameWritten, 0, 2);
                // 两个中文 如 言曌
                if (isChinese(firstWritten) && isChinese(secondWritten)) {
        
                    g2.drawString(nameWritten, 20, 60);
                }
                // 首中次英 如 罗Q
                else if (isChinese(firstWritten) && !isChinese(secondWritten)) {
        
                    g2.drawString(nameWritten, 27, 60);
                    // 首英 如 AB
                } else {
        
                    nameWritten = nameWritten.substring(0,1);
                }
            }
            // 一个字
            if(nameWritten.length() == 1) {
        
                // 中文
                if(isChinese(nameWritten)) {
        
                    font = new Font("微软雅黑", Font.PLAIN, 50);
                    g2.setFont(font);
                    g2.drawString(nameWritten, 25, 70);
                } else {
        
                    font = new Font("微软雅黑", Font.PLAIN, 55);
                    g2.setFont(font);
                    g2.drawString(nameWritten.toUpperCase(), 33, 67);
                }
            }
            return bufferedImage;
        }
    
        /**
         * 根据 name 生成 base64 形式的 文字图
         * @param name String
         * @return String
         */
        public static String generateWZTImgBase64(String name) {
        
            BufferedImage bufferedImage = generateWZTBufferedImage(name);
            //使用hutool提供的工具 把BufferedImage 转为 base64 字符串
            return ImgUtil.toBase64DataUri(bufferedImage, "jpg");
        }
    
        /**
         * 根据 name 生成 File 形式的 文字图
         * @param name String
         * @return File
         */
        public static File generateWZTImgTempFile(String name){
        
            BufferedImage bufferedImage = generateWZTBufferedImage(name);
            //创建1个空白的临时文件 xxxx.jpg
            String tmpDirPath = FileUtil.getTmpDirPath();
            File tempFile = new File(tmpDirPath
                    + "/" + System.currentTimeMillis() + ".jpg");
            try {
        
                //用ImageIO工具类把 BufferedImage 以jpg格式 写入 File
                ImageIO.write(bufferedImage,"jpg",tempFile);
            } catch (IOException e) {
        
                e.printStackTrace();
            }
            return tempFile;
        }
    }

### 测试效果 ###

@Test
        void testWenZiTu() {
        
            //生成base64文字图
            String base64 = AvatarBuildUtil.generateWZTImgBase64("张飞");
            System.out.println(base64);
            
            //生成一个临时file,返回file的绝对路径
            File file = AvatarBuildUtil.generateWZTImgTempFile("琳琅天");
            System.out.println(file.getAbsolutePath());
        }

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    C:\Users\ADMINI~1\AppData\Local\Temp\1686130217116.jpg

![在这里插入图片描述][efa502e9332945b48a024948732f0365.png]

[efa502e9332945b48a024948732f0365.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/16/99fe79d52bca477e8dae792348d47cdb.png