Java tutorial
/** * Copyright (C) 2007 Asterios Raptis * * Licensed 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. */ package net.sourceforge.jaulp.file.read; import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.Reader; import java.nio.charset.Charset; import java.util.ArrayList; import java.util.List; import java.util.Properties; import java.util.logging.Level; import java.util.logging.Logger; import net.sourceforge.jaulp.file.FileConst; import net.sourceforge.jaulp.io.StreamUtils; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.ArrayUtils; /** * The Class ReadFileUtils helps you reading files. * * @version 1.0 * @author Asterios Raptis */ public final class ReadFileUtils { /** * Private constructor. */ private ReadFileUtils() { super(); } /** The LOGGER. */ private static final Logger LOGGER = Logger.getLogger(ReadFileUtils.class.getName()); /** * Get a byte array from the given file. * * @param tmpFile * The file. * @return Returns a byte array or null. */ public static byte[] toByteArray(final File tmpFile) { byte[] data = null; BufferedInputStream bis = null; ByteArrayOutputStream bos = null; if (tmpFile.exists() && !tmpFile.isDirectory()) { try { bos = new ByteArrayOutputStream(FileConst.KILOBYTE); bis = new BufferedInputStream(new FileInputStream(tmpFile)); StreamUtils.writeInputStreamToOutputStream(bis, bos, false); data = bos.toByteArray(); } catch (final IOException e) { LOGGER.log(Level.SEVERE, "transformFilecontentToByteArray failed...\n" + e.getMessage(), e); } finally { StreamUtils.closeInputStream(bis); StreamUtils.closeOutputStream(bos); } } return data; } /** * Get a byte array from the given {@code InputStream}. * * @param input * The {@code InputStream}. * @return the a byte array. * @throws NullPointerException if the input is null * @throws IOException * Signals that an I/O exception has occurred. */ public static byte[] toByteArray(InputStream input) throws IOException { return IOUtils.toByteArray(input); } /** * Get a Byte array from the given file. * * @param tmpFile * the tmp file * @return the filecontent as Byte array object. */ public static Byte[] getFilecontentAsByteObjectArray(final File tmpFile) { return toObject(toByteArray(tmpFile)); } /** * The Method inputStream2String() reads the data from the InputStream into a String. * * @param inputStream * The InputStream from where we read. * @return The String that we read from the InputStream. */ public static String inputStream2String(final InputStream inputStream) { return inputStream2String(inputStream, Charset.forName("UTF-8")); } /** * The Method inputStream2String() reads the data from the InputStream into a String. * * @param inputStream * The InputStream from where we read. * @param encoding * the encoding * @return The String that we read from the InputStream. */ public static String inputStream2String(final InputStream inputStream, Charset encoding) { return ReadFileUtils.reader2String(new InputStreamReader(inputStream, encoding)); } /** * The Method openFileReader() opens a BufferedReader from the given file. * * @param fileName * The file from where to read. * @return The opened BufferedReader from the specified file. * @throws IOException * Signals that an I/O exception has occurred. */ public static Reader openFileReader(final String fileName) throws IOException { BufferedReader bufferedReader = null; final File file = new File(fileName); bufferedReader = (BufferedReader) StreamUtils.getReader(file); return bufferedReader; } /** * The Method reader2String() reads the data from the Reader into a String. * * @param reader * The Reader from where we read. * @return The String that we read from the Reader. */ public static String reader2String(final Reader reader) { final StringBuffer stringBuffer = new StringBuffer(); final char[] charArray = new char[FileConst.BLOCKSIZE]; int tmp; try { while ((tmp = reader.read(charArray)) > 0) { stringBuffer.append(charArray, 0, tmp); } } catch (final IOException e) { LOGGER.log(Level.SEVERE, "reader2String failed...\n" + e.getMessage(), e); } finally { StreamUtils.closeReader(reader); } return stringBuffer.toString(); } /** * Get a byte array from the given file. * * @param file * The file. * @return Returns a byte array or null. */ public static byte[] readFileToBytearray(final File file) { return toByteArray(file); } /** * The Method readFromFile() reads the filecontent to a String. * * @param file * The File to read to a String. * @return The String from the File. * @throws IOException * Signals that an I/O exception has occurred. */ public static String readFromFile(final File file) throws IOException { return inputStream2String(StreamUtils.getInputStream(file)); } public static String readFromFile(final File file, Charset encoding) throws IOException { return inputStream2String(StreamUtils.getInputStream(file), encoding); } /** * The Method readHeadLine() opens the File and reads the first line from the file. * * @param inputFile * The Path to the File and name from the file from where we read. * @return The first line from the file. */ public static String readHeadLine(final String inputFile) { BufferedReader reader = null; String headLine = null; try { reader = new BufferedReader(new FileReader(inputFile)); headLine = reader.readLine(); reader.close(); } catch (final FileNotFoundException e) { LOGGER.log(Level.SEVERE, "readHeadLine failed...\n" + e.getMessage(), e); } catch (final IOException e) { LOGGER.log(Level.SEVERE, "readHeadLine failed...\n" + e.getMessage(), e); } finally { StreamUtils.closeReader(reader); } return headLine; } /** * Reads every line from the File and puts them to the List. * * @param input * The File from where the input comes. * @return The List with all lines from the file. * @throws FileNotFoundException * is thrown if the given file is not found. * @throws IOException * When a io-problem occurs. */ public static List<String> readLinesInList(final File input) throws FileNotFoundException, IOException { return readLinesInList(new FileInputStream(input)); } /** * Reads every line from the given InputStream and puts them to the List. * * @param input * The InputStream from where the input comes. * @return The List with all lines from the file. * @throws FileNotFoundException * is thrown if the given file is not found. * @throws IOException * When a io-problem occurs. */ public static List<String> readLinesInList(final InputStream input) throws IOException { // The List where the lines from the File to save. final List<String> output = new ArrayList<>(); InputStreamReader isr = null; BufferedReader reader = null; try { // create the inputstreamreader isr = new InputStreamReader(input); // create the bufferedreader reader = new BufferedReader(isr); // the line. String line = null; // read all lines from the file do { line = reader.readLine(); // if null break the loop if (line == null) { break; } // add the line to the list output.add(line); } while (true); } finally { StreamUtils.closeReader(isr); StreamUtils.closeReader(reader); } // return the list with all lines from the file. return output; } /** * The Method readFromFile(String) reads from the properties-file all Properties and saves them * into a Properties-Object. * * @param filename * The Filename from the Properties-file. * @return The Properties or null if an error occurs. */ public static Properties readPropertiesFromFile(final String filename) { final Properties properties = new Properties(); FileInputStream fis = null; try { fis = new FileInputStream(filename); properties.load(fis); } catch (final IOException e) { LOGGER.log(Level.SEVERE, "readPropertiesFromFile failed...\n" + e.getMessage(), e); } finally { StreamUtils.closeInputStream(fis); } return properties; } /** * To byte array. * * @param byteArray * the byte array * @return the byte[] */ private static Byte[] toObject(byte[] byteArray) { return ArrayUtils.toObject(byteArray); } }