Java tutorial
/* * 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. */ package org.apache.commons.compress.archivers.examples; import java.io.BufferedInputStream; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.nio.channels.Channels; import java.nio.channels.FileChannel; import java.nio.channels.SeekableByteChannel; import java.nio.file.Files; import java.nio.file.StandardOpenOption; import java.util.Enumeration; import org.apache.commons.compress.archivers.ArchiveEntry; import org.apache.commons.compress.archivers.ArchiveException; import org.apache.commons.compress.archivers.ArchiveInputStream; import org.apache.commons.compress.archivers.ArchiveStreamFactory; import org.apache.commons.compress.archivers.sevenz.SevenZFile; import org.apache.commons.compress.archivers.zip.ZipArchiveEntry; import org.apache.commons.compress.archivers.zip.ZipFile; import org.apache.commons.compress.utils.IOUtils; /** * Provides a high level API for expanding archives. * @since 1.17 */ public class Expander { private interface ArchiveEntrySupplier { ArchiveEntry getNextReadableEntry() throws IOException; } private interface EntryWriter { void writeEntryDataTo(ArchiveEntry entry, OutputStream out) throws IOException; } /** * Expands {@code archive} into {@code targetDirectory}. * * <p>Tries to auto-detect the archive's format.</p> * * @param archive the file to expand * @param targetDirectory the directory to write to * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(File archive, File targetDirectory) throws IOException, ArchiveException { String format = null; try (InputStream i = new BufferedInputStream(Files.newInputStream(archive.toPath()))) { format = new ArchiveStreamFactory().detect(i); } expand(format, archive, targetDirectory); } /** * Expands {@code archive} into {@code targetDirectory}. * * @param archive the file to expand * @param targetDirectory the directory to write to * @param format the archive format. This uses the same format as * accepted by {@link ArchiveStreamFactory}. * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(String format, File archive, File targetDirectory) throws IOException, ArchiveException { if (prefersSeekableByteChannel(format)) { try (SeekableByteChannel c = FileChannel.open(archive.toPath(), StandardOpenOption.READ)) { expand(format, c, targetDirectory); } return; } try (InputStream i = new BufferedInputStream(Files.newInputStream(archive.toPath()))) { expand(format, i, targetDirectory); } } /** * Expands {@code archive} into {@code targetDirectory}. * * <p>Tries to auto-detect the archive's format.</p> * * @param archive the file to expand * @param targetDirectory the directory to write to * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(InputStream archive, File targetDirectory) throws IOException, ArchiveException { expand(new ArchiveStreamFactory().createArchiveInputStream(archive), targetDirectory); } /** * Expands {@code archive} into {@code targetDirectory}. * * @param archive the file to expand * @param targetDirectory the directory to write to * @param format the archive format. This uses the same format as * accepted by {@link ArchiveStreamFactory}. * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(String format, InputStream archive, File targetDirectory) throws IOException, ArchiveException { expand(new ArchiveStreamFactory().createArchiveInputStream(format, archive), targetDirectory); } /** * Expands {@code archive} into {@code targetDirectory}. * * @param archive the file to expand * @param targetDirectory the directory to write to * @param format the archive format. This uses the same format as * accepted by {@link ArchiveStreamFactory}. * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(String format, SeekableByteChannel archive, File targetDirectory) throws IOException, ArchiveException { if (!prefersSeekableByteChannel(format)) { expand(format, Channels.newInputStream(archive), targetDirectory); } else if (ArchiveStreamFactory.ZIP.equalsIgnoreCase(format)) { expand(new ZipFile(archive), targetDirectory); } else if (ArchiveStreamFactory.SEVEN_Z.equalsIgnoreCase(format)) { expand(new SevenZFile(archive), targetDirectory); } else { // never reached as prefersSeekableByteChannel only returns true for ZIP and 7z throw new ArchiveException("don't know how to handle format " + format); } } /** * Expands {@code archive} into {@code targetDirectory}. * * @param archive the file to expand * @param targetDirectory the directory to write to * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(final ArchiveInputStream archive, File targetDirectory) throws IOException, ArchiveException { expand(new ArchiveEntrySupplier() { @Override public ArchiveEntry getNextReadableEntry() throws IOException { ArchiveEntry next = archive.getNextEntry(); while (next != null && !archive.canReadEntryData(next)) { next = archive.getNextEntry(); } return next; } }, new EntryWriter() { @Override public void writeEntryDataTo(ArchiveEntry entry, OutputStream out) throws IOException { IOUtils.copy(archive, out); } }, targetDirectory); } /** * Expands {@code archive} into {@code targetDirectory}. * * @param archive the file to expand * @param targetDirectory the directory to write to * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(final ZipFile archive, File targetDirectory) throws IOException, ArchiveException { final Enumeration<ZipArchiveEntry> entries = archive.getEntries(); expand(new ArchiveEntrySupplier() { @Override public ArchiveEntry getNextReadableEntry() throws IOException { ZipArchiveEntry next = entries.hasMoreElements() ? entries.nextElement() : null; while (next != null && !archive.canReadEntryData(next)) { next = entries.hasMoreElements() ? entries.nextElement() : null; } return next; } }, new EntryWriter() { @Override public void writeEntryDataTo(ArchiveEntry entry, OutputStream out) throws IOException { try (InputStream in = archive.getInputStream((ZipArchiveEntry) entry)) { IOUtils.copy(in, out); } } }, targetDirectory); } /** * Expands {@code archive} into {@code targetDirectory}. * * @param archive the file to expand * @param targetDirectory the directory to write to * @throws IOException if an I/O error occurs * @throws ArchiveException if the archive cannot be read for other reasons */ public void expand(final SevenZFile archive, File targetDirectory) throws IOException, ArchiveException { expand(new ArchiveEntrySupplier() { @Override public ArchiveEntry getNextReadableEntry() throws IOException { return archive.getNextEntry(); } }, new EntryWriter() { @Override public void writeEntryDataTo(ArchiveEntry entry, OutputStream out) throws IOException { final byte[] buffer = new byte[8024]; int n = 0; long count = 0; while (-1 != (n = archive.read(buffer))) { out.write(buffer, 0, n); count += n; } } }, targetDirectory); } private boolean prefersSeekableByteChannel(String format) { return ArchiveStreamFactory.ZIP.equalsIgnoreCase(format) || ArchiveStreamFactory.SEVEN_Z.equalsIgnoreCase(format); } private void expand(ArchiveEntrySupplier supplier, EntryWriter writer, File targetDirectory) throws IOException { String targetDirPath = targetDirectory.getCanonicalPath(); if (!targetDirPath.endsWith(File.separator)) { targetDirPath += File.separatorChar; } ArchiveEntry nextEntry = supplier.getNextReadableEntry(); while (nextEntry != null) { File f = new File(targetDirectory, nextEntry.getName()); if (!f.getCanonicalPath().startsWith(targetDirPath)) { throw new IOException( "expanding " + nextEntry.getName() + " would create file outside of " + targetDirectory); } if (nextEntry.isDirectory()) { if (!f.isDirectory() && !f.mkdirs()) { throw new IOException("failed to create directory " + f); } } else { File parent = f.getParentFile(); if (!parent.isDirectory() && !parent.mkdirs()) { throw new IOException("failed to create directory " + parent); } try (OutputStream o = Files.newOutputStream(f.toPath())) { writer.writeEntryDataTo(nextEntry, o); } } nextEntry = supplier.getNextReadableEntry(); } } }