java 获取文件后缀及根据文件扩展名判断文件是否图片格式

public class ImageUtil {

    public static String pngSuffix = "png";

    public static String jpgSuffix = "jpg";

    public static String jpegSuffix = "jpeg";

    public static String bmpSuffix = "bmp";

    
    public static String getFileExtension(String fileName) {
        String extension = fileName.substring(fileName.lastIndexOf(".") + 1);
        return extension;
    }

    
    public static boolean isImage(String fileName) {
        String extension = getFileExtension(fileName);
        String[] imageExtension = new String[]{"jpeg", "jpg", "bmp", "png"};

        for (String e : imageExtension){
            if (extension.toLowerCase().equals(e)) {
                return true;
            }
        }

        return false;
    }
}