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.pulsar.io.file.utils; import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.Closeable; import java.io.DataInputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.UncheckedIOException; import java.nio.file.Files; import java.nio.file.Path; import java.util.stream.Stream; import java.util.zip.ZipInputStream; import org.apache.commons.io.IOUtils; /** * Helper class that provides helper methods for working with * zip-formatted files. */ public class ZipFiles { /** * Returns true if the given file is a gzip file. */ @SuppressWarnings("deprecation") public static boolean isZip(File f) { InputStream input = null; try { DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream(f))); int test = in.readInt(); in.close(); return test == 0x504b0304; } catch (final Exception e) { return false; } finally { IOUtils.closeQuietly(input); } } /** * Get a lazily loaded stream of lines from a gzipped file, similar to * {@link Files#lines(java.nio.file.Path)}. * * @param path * The path to the zipped file. * @return stream with lines. */ public static Stream<String> lines(Path path) { ZipInputStream zipStream = null; try { zipStream = new ZipInputStream(Files.newInputStream(path)); } catch (IOException e) { closeSafely(zipStream); throw new UncheckedIOException(e); } // Reader decoder = new InputStreamReader(gzipStream, Charset.defaultCharset()); BufferedReader reader = new BufferedReader(new InputStreamReader(zipStream)); return reader.lines().onClose(() -> closeSafely(reader)); } private static void closeSafely(Closeable closeable) { if (closeable != null) { try { closeable.close(); } catch (IOException e) { // Ignore } } } }