Java tutorial
/* * Copyright (C) 2016 by Vashistha kumar * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package com.vk.crawler.core.util; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.nio.file.Files; import java.nio.file.Paths; import java.util.ArrayList; import java.util.List; import java.util.UUID; import org.apache.commons.io.IOUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class FileUtils { private static final Logger logger = LoggerFactory.getLogger(FileUtils.class); public static String getFileExtension(String fileName) { if (StringUtils.isEmpty(fileName)) { return null; } String extension = ""; int i = fileName.lastIndexOf('.'); // the case that a directory may have a '.', but the filename itself doesn't (like /path/to.a/file), String temp = fileName.substring(i + 1); if (!temp.contains("/") && !temp.contains("\\")) { extension = temp; } return extension; } /** * assuming last word in absolutePath is file name and not a directory. * @param absolutePath * @return */ public static String getFileName(String absolutePath) { if (StringUtils.isEmpty(absolutePath)) { return null; } int lastIndex = absolutePath.lastIndexOf("\\"); if (lastIndex == -1) { lastIndex = absolutePath.lastIndexOf("/"); } if (lastIndex == -1) { return absolutePath; } return absolutePath.substring(lastIndex + 1); } /** * Assuming last word in absolute path is file name. * @param absolutePath * @return */ public static String getFileNameWithoutExtension(String absolutePath) { String fileName = getFileName(absolutePath); if (fileName != null && fileName.contains(".")) { return fileName.substring(0, fileName.lastIndexOf(".")); } return fileName; } /** * In real cms file name should be UUID.extension. But here to search file system manually, name of file is appended with UUID * @param absolutePath * @return */ public static String getUniqueFileName(String absolutePath) { String fileName = getFileNameWithoutExtension(absolutePath); String extension = getFileExtension(absolutePath); return StringUtils.isEmpty(extension) ? fileName + UUID.randomUUID() : fileName + UUID.randomUUID() + "." + extension; } public static void saveFile(InputStream inStream, String fileName, String outFilePath) throws Exception { try { createFile(inStream, fileName, outFilePath); } catch (Exception e) { logger.error("saving document " + e); } finally { if (inStream != null) { inStream.close(); } } } public static List<Boolean> saveFile(InputStream inStream, String fileName, String outFilePath, String tempPath) throws Exception { List<Boolean> created = new ArrayList<Boolean>(); try { byte[] bytes = IOUtils.toByteArray(inStream); boolean createdOnSAN = createFile(bytes, fileName, outFilePath); created.add(createdOnSAN); boolean createdOnTemp = createFile(bytes, fileName, tempPath); created.add(createdOnTemp); } catch (Exception e) { logger.error("saving document " + e); } finally { if (inStream != null) { inStream.close(); } } return created; } public static boolean createFile(byte[] bytes, String fileName, String outFilePath) { boolean rtn = false; try { if (StringUtils.isEmpty(outFilePath) || StringUtils.isEmpty(fileName)) { return rtn; } Files.createDirectories(Paths.get(outFilePath)); Files.write(Paths.get(outFilePath + File.separator + fileName), bytes); logger.info("File " + fileName + " saved successfully at " + outFilePath); rtn = true; } catch (Exception e) { } return rtn; } public static boolean createFile(InputStream inStream, String fileName, String outFilePath) throws Exception { //TODO use apache common-io methods. UPDATE- Apache.io is less efficient than Java 7 OutputStream outStream = null; boolean rtn = false; try { if (StringUtils.isEmpty(outFilePath) || StringUtils.isEmpty(fileName)) { return rtn; } Files.createDirectories(Paths.get(outFilePath)); logger.info("writing file " + fileName + " to directory " + outFilePath); outStream = new FileOutputStream(new File(outFilePath, fileName)); int read = 0; byte[] bytes = new byte[1024]; while ((read = inStream.read(bytes)) != -1) { outStream.write(bytes, 0, read); } logger.info("file " + fileName + " saved successfully."); rtn = true; } catch (Exception e) { logger.error("saving document " + e); } finally { if (outStream != null) { try { outStream.flush(); outStream.close(); } catch (Exception e) { logger.error("Error in finally."); } } } return rtn; } public static List<String> readLines(String fileNameWithAbsolutePath) { List<String> lines = new ArrayList<String>(); try { lines = org.apache.commons.io.FileUtils.readLines(new File(fileNameWithAbsolutePath), "UTF-8"); } catch (IOException e) { logger.error("", e); } return lines; } }