content: package com.alibaba.excel.util;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.UUID;
  
  import com.alibaba.excel.exception.ExcelAnalysisException;
  import com.alibaba.excel.exception.ExcelCommonException;
  
  import org.apache.poi.util.TempFile;
  
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * @author Apache Software Foundation (ASF)
   */
  public class FileUtils {
      public static final String POI_FILES = "poifiles";
      public static final String EX_CACHE = "excache";
      /**
       * If a server has multiple projects in use at the same time, a directory with the same name will be created under
       * the temporary directory, but each project is run by a different user, so there is a permission problem, so each
       * project creates a unique UUID as a separate Temporary Files.
       */
      private static String tempFilePrefix =
          System.getProperty(TempFile.JAVA_IO_TMPDIR) + File.separator + UUID.randomUUID().toString() + File.separator;
      /**
       * Used to store poi temporary files.
       */
      private static String poiFilesPath = tempFilePrefix + POI_FILES + File.separator;
      /**
       * Used to store easy excel temporary files.
       */
      private static String cachePath = tempFilePrefix + EX_CACHE + File.separator;
  
      private static final int WRITE_BUFF_SIZE = 8192;
  
      private FileUtils() {}
  
      static {
          // Create a temporary directory in advance
          File tempFile = new File(tempFilePrefix);
          createDirectory(tempFile);
          tempFile.deleteOnExit();
          // Initialize the cache directory
          File cacheFile = new File(cachePath);
          createDirectory(cacheFile);
      }
  
      /**
       * Reads the contents of a file into a byte array. * The file is always closed.
       *
       * @param file
       * @return
       * @throws IOException
       */
      public static byte[] readFileToByteArray(final File file) throws IOException {
          InputStream in = openInputStream(file);
          try {
              final long fileLength = file.length();
              return fileLength > 0 ? IoUtils.toByteArray(in, (int)fileLength) : IoUtils.toByteArray(in);
          } finally {
              in.close();
          }
      }
  
      /**
       * Opens a {@link FileInputStream} for the specified file, providing better error messages than simply calling
       * <code>new FileInputStream(file)</code>.
       * <p>
       * At the end of the method either the stream will be successfully opened, or an exception will have been thrown.
       * <p>
       * An exception is thrown if the file does not exist. An exception is thrown if the file object exists but is a
       * directory. An exception is thrown if the file exists but cannot be read.
       *
       * @param file
       * @return
       * @throws IOException
       */
      public static FileInputStream openInputStream(final File file) throws IOException {
          if (file.exists()) {
              if (file.isDirectory()) {
                  throw new IOException("File '" + file + "' exists but is a directory");
              }
              if (file.canRead() == false) {
                  throw new IOException("File '" + file + "' cannot be read");
              }
          } else {
              throw new FileNotFoundException("File '" + file + "' does not exist");
          }
          return new FileInputStream(file);
      }
  
      /**
       * Write inputStream to file
       *
       * @param file        file
       * @param inputStream inputStream
       */
      public static void writeToFile(File file, InputStream inputStream) {
          writeToFile(file, inputStream, true);
      }
  
      /**
       * Write inputStream to file
       *
       * @param file             file
       * @param inputStream      inputStream
       * @param closeInputStream closeInputStream
       */
      public static void writeToFile(File file, InputStream inputStream, boolean closeInputStream) {
          OutputStream outputStream = null;
          try {
              outputStream = new FileOutputStream(file);
              int bytesRead;
              byte[] buffer = new byte[WRITE_BUFF_SIZE];
              while ((bytesRead = inputStream.read(buffer, 0, WRITE_BUFF_SIZE)) != -1) {
                  outputStream.write(buffer, 0, bytesRead);
              }
          } catch (Exception e) {
              throw new ExcelAnalysisException("Can not create temporary file!", e);
          } finally {
              if (outputStream != null) {
                  try {
                      outputStream.close();
                  } catch (IOException e) {
                      throw new ExcelAnalysisException("Can not close 'outputStream'!", e);
                  }
              }
              if (inputStream != null && closeInputStream) {
                  try {
                      inputStream.close();
                  } catch (IOException e) {
                      throw new ExcelAnalysisException("Can not close 'inputStream'", e);
                  }
              }
          }
      }
  
      public static void createPoiFilesDirectory() {
          TempFile.setTempFileCreationStrategy(new EasyExcelTempFileCreationStrategy());
      }
  
      public static File createCacheTmpFile() {
          return createDirectory(new File(cachePath + UUID.randomUUID().toString()));
      }
  
      public static File createTmpFile(String fileName) {
          File directory = createDirectory(new File(tempFilePrefix));
          return new File(directory, fileName);
      }
  
      /**
       * @param directory
       */
      public static File createDirectory(File directory) {
          if (!directory.exists() && !directory.mkdirs()) {
              throw new ExcelCommonException("Cannot create directory:" + directory.getAbsolutePath());
          }
          return directory;
      }
  
      /**
       * delete file
       *
       * @param file
       */
      public static void delete(File file) {
          if (file.isFile()) {
              file.delete();
              return;
          }
          if (file.isDirectory()) {
              File[] childFiles = file.listFiles();
              if (childFiles == null || childFiles.length == 0) {
                  file.delete();
                  return;
              }
              for (int i = 0; i < childFiles.length; i++) {
                  delete(childFiles[i]);
              }
              file.delete();
          }
      }
  
      public static String getTempFilePrefix() {
          return tempFilePrefix;
      }
  
      public static void setTempFilePrefix(String tempFilePrefix) {
          FileUtils.tempFilePrefix = tempFilePrefix;
      }
  
      public static String getPoiFilesPath() {
          return poiFilesPath;
      }
  
      public static void setPoiFilesPath(String poiFilesPath) {
          FileUtils.poiFilesPath = poiFilesPath;
      }
  
      public static String getCachePath() {
          return cachePath;
      }
  
      public static void setCachePath(String cachePath) {
          FileUtils.cachePath = cachePath;
      }
  }
  