java FileTypeUtils文件类型工具类，FileUtils文件工具类，ImageUtils图片工具类

/**
 * 文件类型工具类
 *
 * @author ruoyi
 */
public class FileTypeUtils
{
    /**
     * 获取文件类型
     * <p>
     * 例如: ruoyi.txt, 返回: txt
     * 
     * @param file 文件名
     * @return 后缀（不含".")
     */
    public static String getFileType(File file)
    {
        if (null == file)
        {
            return StringUtils.EMPTY;
        }
        return getFileType(file.getName());
    }

    /**
     * 获取文件类型
     * <p>
     * 例如: ruoyi.txt, 返回: txt
     *
     * @param fileName 文件名
     * @return 后缀（不含".")
     */
    public static String getFileType(String fileName)
    {
        int separatorIndex = fileName.lastIndexOf(".");
        if (separatorIndex < 0)
        {
            return "";
        }
        return fileName.substring(separatorIndex + 1).toLowerCase();
    }

    /**
     * 获取文件类型
     * 
     * @param photoByte 文件字节码
     * @return 后缀（不含".")
     */
    public static String getFileExtendName(byte[] photoByte)
    {
        String strFileExtendName = "JPG";
        if ((photoByte[0] == 71) && (photoByte[1] == 73) && (photoByte[2] == 70) && (photoByte[3] == 56)
                && ((photoByte[4] == 55) || (photoByte[4] == 57)) && (photoByte[5] == 97))
        {
            strFileExtendName = "GIF";
        }
        else if ((photoByte[6] == 74) && (photoByte[7] == 70) && (photoByte[8] == 73) && (photoByte[9] == 70))
        {
            strFileExtendName = "JPG";
        }
        else if ((photoByte[0] == 66) && (photoByte[1] == 77))
        {
            strFileExtendName = "BMP";
        }
        else if ((photoByte[1] == 80) && (photoByte[2] == 78) && (photoByte[3] == 71))
        {
            strFileExtendName = "PNG";
        }
        return strFileExtendName;
    }
}

/**
 * 文件处理工具类
 * 
 * @author ruoyi
 */
public class FileUtils
{
    public static String FILENAME_PATTERN = "[a-zA-Z0-9_\\-\\|\\.\\u4e00-\\u9fa5]+";

    /**
     * 输出指定文件的byte数组
     * 
     * @param filePath 文件路径
     * @param os 输出流
     * @return
     */
    public static void writeBytes(String filePath, OutputStream os) throws IOException
    {
        FileInputStream fis = null;
        try
        {
            File file = new File(filePath);
            if (!file.exists())
            {
                throw new FileNotFoundException(filePath);
            }
            fis = new FileInputStream(file);
            byte[] b = new byte[1024];
            int length;
            while ((length = fis.read(b)) > 0)
            {
                os.write(b, 0, length);
            }
        }
        catch (IOException e)
        {
            throw e;
        }
        finally
        {
            IOUtils.close(os);
            IOUtils.close(fis);
        }
    }

    /**
     * 写数据到文件中
     *
     * @param data 数据
     * @return 目标文件
     * @throws IOException IO异常
     */
    public static String writeImportBytes(byte[] data) throws IOException
    {
        return writeBytes(data, RuoYiConfig.getImportPath());
    }

    /**
     * 写数据到文件中
     *
     * @param data 数据
     * @param uploadDir 目标文件
     * @return 目标文件
     * @throws IOException IO异常
     */
    public static String writeBytes(byte[] data, String uploadDir) throws IOException
    {
        FileOutputStream fos = null;
        String pathName = "";
        try
        {
            String extension = getFileExtendName(data);
            pathName = DateUtils.datePath() + "/" + IdUtils.fastUUID() + "." + extension;
            File file = FileUploadUtils.getAbsoluteFile(uploadDir, pathName);
            fos = new FileOutputStream(file);
            fos.write(data);
        }
        finally
        {
            IOUtils.close(fos);
        }
        return FileUploadUtils.getPathFileName(uploadDir, pathName);
    }

    /**
     * 删除文件
     * 
     * @param filePath 文件
     * @return
     */
    public static boolean deleteFile(String filePath)
    {
        boolean flag = false;
        File file = new File(filePath);
        // 路径为文件且不为空则进行删除
        if (file.isFile() && file.exists())
        {
            file.delete();
            flag = true;
        }
        return flag;
    }

    /**
     * 文件名称验证
     * 
     * @param filename 文件名称
     * @return true 正常 false 非法
     */
    public static boolean isValidFilename(String filename)
    {
        return filename.matches(FILENAME_PATTERN);
    }

    /**
     * 检查文件是否可下载
     * 
     * @param resource 需要下载的文件
     * @return true 正常 false 非法
     */
    public static boolean checkAllowDownload(String resource)
    {
        // 禁止目录上跳级别
        if (StringUtils.contains(resource, ".."))
        {
            return false;
        }

        // 检查允许下载的文件规则
        if (ArrayUtils.contains(MimeTypeUtils.DEFAULT_ALLOWED_EXTENSION, FileTypeUtils.getFileType(resource)))
        {
            return true;
        }

        // 不在允许下载的文件规则
        return false;
    }

    /**
     * 下载文件名重新编码
     * 
     * @param request 请求对象
     * @param fileName 文件名
     * @return 编码后的文件名
     */
    public static String setFileDownloadHeader(HttpServletRequest request, String fileName) throws UnsupportedEncodingException
    {
        final String agent = request.getHeader("USER-AGENT");
        String filename = fileName;
        if (agent.contains("MSIE"))
        {
            // IE浏览器
            filename = URLEncoder.encode(filename, "utf-8");
            filename = filename.replace("+", " ");
        }
        else if (agent.contains("Firefox"))
        {
            // 火狐浏览器
            filename = new String(fileName.getBytes(), "ISO8859-1");
        }
        else if (agent.contains("Chrome"))
        {
            // google浏览器
            filename = URLEncoder.encode(filename, "utf-8");
        }
        else
        {
            // 其它浏览器
            filename = URLEncoder.encode(filename, "utf-8");
        }
        return filename;
    }

    /**
     * 下载文件名重新编码
     *
     * @param response 响应对象
     * @param realFileName 真实文件名
     */
    public static void setAttachmentResponseHeader(HttpServletResponse response, String realFileName) throws UnsupportedEncodingException
    {
        String percentEncodedFileName = percentEncode(realFileName);

        StringBuilder contentDispositionValue = new StringBuilder();
        contentDispositionValue.append("attachment; filename=")
                .append(percentEncodedFileName)
                .append(";")
                .append("filename*=")
                .append("utf-8''")
                .append(percentEncodedFileName);

        response.addHeader("Access-Control-Expose-Headers", "Content-Disposition,download-filename");
        response.setHeader("Content-disposition", contentDispositionValue.toString());
        response.setHeader("download-filename", percentEncodedFileName);
    }

    /**
     * 百分号编码工具方法
     *
     * @param s 需要百分号编码的字符串
     * @return 百分号编码后的字符串
     */
    public static String percentEncode(String s) throws UnsupportedEncodingException
    {
        String encode = URLEncoder.encode(s, StandardCharsets.UTF_8.toString());
        return encode.replaceAll("\\+", "%20");
    }

    /**
     * 获取图像后缀
     * 
     * @param photoByte 图像数据
     * @return 后缀名
     */
    public static String getFileExtendName(byte[] photoByte)
    {
        String strFileExtendName = "jpg";
        if ((photoByte[0] == 71) && (photoByte[1] == 73) && (photoByte[2] == 70) && (photoByte[3] == 56)
                && ((photoByte[4] == 55) || (photoByte[4] == 57)) && (photoByte[5] == 97))
        {
            strFileExtendName = "gif";
        }
        else if ((photoByte[6] == 74) && (photoByte[7] == 70) && (photoByte[8] == 73) && (photoByte[9] == 70))
        {
            strFileExtendName = "jpg";
        }
        else if ((photoByte[0] == 66) && (photoByte[1] == 77))
        {
            strFileExtendName = "bmp";
        }
        else if ((photoByte[1] == 80) && (photoByte[2] == 78) && (photoByte[3] == 71))
        {
            strFileExtendName = "png";
        }
        return strFileExtendName;
    }

    /**
     * 获取文件名称 /profile/upload/2022/04/16/ruoyi.png -- ruoyi.png
     * 
     * @param fileName 路径名称
     * @return 没有文件路径的名称
     */
    public static String getName(String fileName)
    {
        if (fileName == null)
        {
            return null;
        }
        int lastUnixPos = fileName.lastIndexOf('/');
        int lastWindowsPos = fileName.lastIndexOf('\\');
        int index = Math.max(lastUnixPos, lastWindowsPos);
        return fileName.substring(index + 1);
    }

    /**
     * 获取不带后缀文件名称 /profile/upload/2022/04/16/ruoyi.png -- ruoyi
     * 
     * @param fileName 路径名称
     * @return 没有文件路径和后缀的名称
     */
    public static String getNameNotSuffix(String fileName)
    {
        if (fileName == null)
        {
            return null;
        }
        String baseName = FilenameUtils.getBaseName(fileName);
        return baseName;
    }

}

/**
 * 图片处理工具类
 *
 * @author ruoyi
 */
public class ImageUtils
{
    private static final Logger log = LoggerFactory.getLogger(ImageUtils.class);

    public static byte[] getImage(String imagePath)
    {
        InputStream is = getFile(imagePath);
        try
        {
            return IOUtils.toByteArray(is);
        }
        catch (Exception e)
        {
            log.error("图片加载异常 {}", e);
            return null;
        }
        finally
        {
            IOUtils.closeQuietly(is);
        }
    }

    public static InputStream getFile(String imagePath)
    {
        try
        {
            byte[] result = readFile(imagePath);
            result = Arrays.copyOf(result, result.length);
            return new ByteArrayInputStream(result);
        }
        catch (Exception e)
        {
            log.error("获取图片异常 {}", e);
        }
        return null;
    }

    /**
     * 读取文件为字节数据
     * 
     * @param url 地址
     * @return 字节数据
     */
    public static byte[] readFile(String url)
    {
        InputStream in = null;
        try
        {
            if (url.startsWith("http"))
            {
                // 网络地址
                URL urlObj = new URL(url);
                URLConnection urlConnection = urlObj.openConnection();
                urlConnection.setConnectTimeout(30 * 1000);
                urlConnection.setReadTimeout(60 * 1000);
                urlConnection.setDoInput(true);
                in = urlConnection.getInputStream();
            }
            else
            {
                // 本机地址
                String localPath = RuoYiConfig.getProfile();
                String downloadPath = localPath + StringUtils.substringAfter(url, Constants.RESOURCE_PREFIX);
                in = new FileInputStream(downloadPath);
            }
            return IOUtils.toByteArray(in);
        }
        catch (Exception e)
        {
            log.error("获取文件路径异常 {}", e);
            return null;
        }
        finally
        {
            IOUtils.closeQuietly(in);
        }
    }
}