code: public static String encodeBase64(File targetFile) {
          BufferedImage image = null;
  
          try {
              image = ImageIO.read(targetFile);
          }
          catch (IOException e) {
              throw Lang.wrapThrow(e);
          }
  
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          BufferedOutputStream bos = new BufferedOutputStream(baos);
          image.flush();
          try {
              ImageIO.write(image, Files.getSuffixName(targetFile), bos);
              bos.flush();
              bos.close();
          }
          catch (IOException e) {
              throw Lang.wrapThrow(e);
          }
  
          byte[] bImage = baos.toByteArray();
  
          return Base64.encodeToString(bImage, false);
      }
docs: 生成该图片对应的 Base64 编码的字符串
  
  @param targetFile
  图片文件
  @return 图片对应的 Base64 编码的字符串