Java tutorial
/* * Copyright (c) 2006-2012 Nuxeo SA (http://nuxeo.com/) and others. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Nuxeo - initial API and implementation * */ package org.eclipse.ecr.common.utils; import java.io.BufferedOutputStream; import java.io.BufferedReader; import java.io.Closeable; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.PrintWriter; import java.io.UnsupportedEncodingException; import java.net.MalformedURLException; import java.net.URISyntaxException; import java.net.URL; import java.net.URLDecoder; import java.util.ArrayList; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a> * */ public final class FileUtils { private static final int BUFFER_SIZE = 1024 * 64; // 64K private static final int MAX_BUFFER_SIZE = 1024 * 1024; // 64K private static final int MIN_BUFFER_SIZE = 1024 * 8; // 64K private static final Log log = LogFactory.getLog(FileUtils.class); // This is an utility class private FileUtils() { } public static void safeClose(Closeable stream) { try { stream.close(); } catch (IOException e) { // do nothing } } private static byte[] createBuffer(int preferredSize) { if (preferredSize < 1) { preferredSize = BUFFER_SIZE; } if (preferredSize > MAX_BUFFER_SIZE) { preferredSize = MAX_BUFFER_SIZE; } else if (preferredSize < MIN_BUFFER_SIZE) { preferredSize = MIN_BUFFER_SIZE; } return new byte[preferredSize]; } public static void copy(InputStream in, OutputStream out) throws IOException { byte[] buffer = createBuffer(in.available()); int read; while ((read = in.read(buffer)) != -1) { out.write(buffer, 0, read); } } public static String read(InputStream in) throws IOException { StringBuilder sb = new StringBuilder(); byte[] buffer = createBuffer(in.available()); try { int read; while ((read = in.read(buffer)) != -1) { sb.append(new String(buffer, 0, read)); } } finally { in.close(); } return sb.toString(); } public static byte[] readBytes(URL url) throws IOException { return readBytes(url.openStream()); } public static byte[] readBytes(InputStream in) throws IOException { byte[] buffer = createBuffer(in.available()); int w = 0; try { int read = 0; int len; do { w += read; len = buffer.length - w; if (len <= 0) { // resize buffer byte[] b = new byte[buffer.length + BUFFER_SIZE]; System.arraycopy(buffer, 0, b, 0, w); buffer = b; len = buffer.length - w; } } while ((read = in.read(buffer, w, len)) != -1); } finally { in.close(); } if (buffer.length > w) { // compact buffer byte[] b = new byte[w]; System.arraycopy(buffer, 0, b, 0, w); buffer = b; } return buffer; } public static String readFile(File file) throws IOException { FileInputStream in = null; try { in = new FileInputStream(file); return read(in); } finally { if (in != null) { in.close(); } } } public static List<String> readLines(File file) throws IOException { List<String> lines = new ArrayList<String>(); BufferedReader reader = null; try { InputStream in = new FileInputStream(file); reader = new BufferedReader(new InputStreamReader(in)); String line; while ((line = reader.readLine()) != null) { lines.add(line); } } finally { if (reader != null) { try { reader.close(); } catch (IOException e) { } } } return lines; } public static void writeLines(File file, List<String> lines) throws IOException { PrintWriter out = null; try { out = new PrintWriter(new FileOutputStream(file)); for (String line : lines) { out.println(line); } } finally { if (out != null) { out.close(); } } } public static byte[] readBytes(File file) throws IOException { FileInputStream in = null; try { in = new FileInputStream(file); return readBytes(in); } finally { if (in != null) { in.close(); } } } public static void writeFile(File file, byte[] buf) throws IOException { writeFile(file, buf, false); } /** * @param file * @param buf * @param append * @throws IOException * @since 5.5 */ public static void writeFile(File file, byte[] buf, boolean append) throws IOException { FileOutputStream fos = null; try { fos = new FileOutputStream(file, append); fos.write(buf); } finally { if (fos != null) { fos.close(); } } } public static void writeFile(File file, String buf) throws IOException { writeFile(file, buf.getBytes(), false); } /** * @param dst * @param content * @param append * @throws IOException * @since 5.5 */ public static void writeFile(File file, String buf, boolean append) throws IOException { writeFile(file, buf.getBytes(), append); } public static void download(URL url, File file) throws IOException { InputStream in = url.openStream(); OutputStream out = new FileOutputStream(file); try { copy(in, out); } finally { if (in != null) { in.close(); } out.close(); } } public static void deleteTree(File dir) { emptyDirectory(dir); dir.delete(); } public static void emptyDirectory(File dir) { File[] files = dir.listFiles(); if (files == null) { return; } int len = files.length; for (int i = 0; i < len; i++) { File file = files[i]; if (file.isDirectory()) { deleteTree(file); } else { file.delete(); } } } public static void copyToFile(InputStream in, File file) throws IOException { OutputStream out = null; try { out = new FileOutputStream(file); byte[] buffer = createBuffer(in.available()); int read; while ((read = in.read(buffer)) != -1) { out.write(buffer, 0, read); } } finally { if (out != null) { out.close(); } } } public static void append(File src, File dst) throws IOException { append(src, dst, false); } public static void append(File src, File dst, boolean appendNewLine) throws IOException { InputStream in = null; try { in = new FileInputStream(src); append(in, dst, appendNewLine); } finally { if (in != null) { in.close(); } } } public static void append(InputStream in, File file) throws IOException { append(in, file, false); } public static void append(InputStream in, File file, boolean appendNewLine) throws IOException { OutputStream out = null; try { out = new BufferedOutputStream(new FileOutputStream(file, true)); if (appendNewLine) { out.write(System.getProperty("line.separator").getBytes()); } byte[] buffer = new byte[BUFFER_SIZE]; int read; while ((read = in.read(buffer)) != -1) { out.write(buffer, 0, read); } } finally { if (out != null) { out.close(); } } } /** * Copies source to destination. If source and destination are the same, * does nothing. Both single files and directories are handled. * * @param src the source file or directory * @param dst the destination file or directory * @throws IOException */ public static void copy(File src, File dst) throws IOException { if (src.equals(dst)) { return; } if (src.isFile()) { copyFile(src, dst); } else { copyTree(src, dst); } } public static void copy(File[] src, File dst) throws IOException { for (File file : src) { copy(file, dst); } } public static void copyFile(File src, File dst) throws IOException { if (dst.isDirectory()) { dst = new File(dst, src.getName()); } FileInputStream in = null; FileOutputStream out = new FileOutputStream(dst); try { in = new FileInputStream(src); copy(in, out); } finally { if (in != null) { in.close(); } out.close(); } } /** * Copies recursively source to destination. * <p> * The source file is assumed to be a directory. * * @param src the source directory * @param dst the destination directory * @throws IOException */ public static void copyTree(File src, File dst) throws IOException { if (src.isFile()) { copyFile(src, dst); } else if (src.isDirectory()) { if (dst.exists()) { dst = new File(dst, src.getName()); dst.mkdir(); } else { // allows renaming dest dir dst.mkdirs(); } File[] files = src.listFiles(); for (File file : files) { copyTree(file, dst); } } } public static void copyTree(File src, File dst, PathFilter filter) throws IOException { int rootIndex = src.getPath().length() + 1; for (File file : src.listFiles()) { copyTree(rootIndex, file, new File(dst, file.getName()), filter); } } protected static void copyTree(int rootIndex, File src, File dst, PathFilter filter) throws IOException { if (src.isFile()) { String relPath = src.getPath().substring(rootIndex); if (!filter.accept(new Path(relPath))) { return; } dst.mkdirs(); copyFile(src, dst); } else if (src.isDirectory()) { File[] files = src.listFiles(); for (File file : files) { copyTree(rootIndex, file, new File(dst, file.getName()), filter); } } } /** * Decodes an URL path so that is can be processed as a filename later. * * @param url the Url to be processed. * @return the decoded path. */ public static String getFilePathFromUrl(URL url) { String path = ""; if (url.getProtocol().equals("file")) { try { path = URLDecoder.decode(url.getPath(), "UTF-8"); } catch (UnsupportedEncodingException e) { log.error(e); } } return path; } public static File getFileFromURL(URL url) { File file; String filename = getFilePathFromUrl(url); if (filename.equals("")) { file = null; } else { file = new File(filename); } return file; } public static String getParentPath(String path) { int p = path.lastIndexOf(File.separator); if (p == -1) { return null; } return path.substring(0, p); } public static String getFileName(String path) { int p = path.lastIndexOf(File.separator); if (p == -1) { return path; } return path.substring(p + 1); } public static String getFileExtension(String path) { int p = path.lastIndexOf('.'); if (p == -1) { return null; } return path.substring(p + 1); } public static String getFileNameNoExt(String path) { String name = getFileName(path); int p = name.lastIndexOf('.'); if (p == -1) { return name; } return name.substring(0, p); } /** * Retrieves the total path of a resource from the Thread Context. * * @param resource the resource name to be retrieved. * @return the decoded path. */ public static String getResourcePathFromContext(String resource) { URL url = Thread.currentThread().getContextClassLoader().getResource(resource); return getFilePathFromUrl(url); } public static File getResourceFileFromContext(String resource) { File file; String filename = getResourcePathFromContext(resource); if (filename.equals("")) { file = null; } else { file = new File(filename); } return file; } public static File[] findFiles(File root, String pattern, boolean recurse) { List<File> result = new ArrayList<File>(); if (pattern == null) { if (recurse) { collectFiles(root, result); } else { return root.listFiles(); } } else { FileNamePattern pat = new FileNamePattern(pattern); if (recurse) { collectFiles(root, pat, result); } else { File[] files = root.listFiles(); for (File file : files) { if (pat.match(file.getName())) { result.add(file); } } } } return result.toArray(new File[result.size()]); } public static void collectFiles(File root, FileNamePattern pattern, List<File> result) { File[] files = root.listFiles(); for (File file : files) { if (pattern.match(file.getName())) { result.add(file); if (file.isDirectory()) { collectFiles(file, pattern, result); } } } } public static void collectFiles(File root, List<File> result) { File[] files = root.listFiles(); for (File file : files) { result.add(file); if (file.isDirectory()) { collectFiles(file, result); } } } public static void close(InputStream in) { if (in != null) { try { in.close(); } catch (IOException e) { log.error(e); } } } public static void close(OutputStream out) { if (out != null) { try { out.close(); } catch (IOException e) { log.error(e); } } } /** * Create a file handler (this doesn't create a real file) given a file URI. * This method can be used to create files from invalid URL strings (e.g. * containing spaces ..) * * @return a file object */ public static File urlToFile(String url) throws MalformedURLException { return urlToFile(new URL(url)); } public static File urlToFile(URL url) { try { return new File(url.toURI()); } catch (URISyntaxException e) { return new File(url.getPath()); } } public static List<String> readLines(InputStream in) throws IOException { List<String> lines = new ArrayList<String>(); BufferedReader reader = null; try { reader = new BufferedReader(new InputStreamReader(in)); String line; while ((line = reader.readLine()) != null) { lines.add(line); } } finally { if (reader != null) { try { reader.close(); } catch (IOException e) { } } } return lines; } /** * Compares two files content as String even if their EOL are differents * * @param expected a file content with Windows or Unix like EOL * @param source another file content with Windows or Unix like EOL * @return the result of equals after replacing their EOL */ public static boolean areFilesContentEquals(String expected, String source) { if (expected == source) { return true; } if (expected == null || source == null) { return false; } if (expected.length() != source.length()) { // Prevent from comparing files with Windows EOL return expected.replace("\r\n", "\n").equals(source.replace("\r\n", "\n")); } else { return expected.equals(source); } } }