1 /* 2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.io; 27 28 import java.nio.CharBuffer; 29 30 /** 31 * Utility methods for copying data between a {@link InputStream} and 32 * {@link OutputStream} or between a {@link Readable} and a {@link Appendable}. 33 */ 34 public final class IOUtil { 35 36 // buffer size used for reading and writing 37 private static final int BUFFER_SIZE = 8192; 38 39 private IOUtil() { 40 throw new Error("no instances"); 41 } 42 43 /** 44 * Reads all bytes from an input stream and writes them to an output stream. 45 * 46 * @param source the input stream to read from 47 * @param target the output stream to write to 48 * 49 * @return the number of bytes successfully read and written 50 * 51 * @throws IOException if an I/O error occurs when reading or writing 52 */ 53 public static long copy(InputStream source, OutputStream target) 54 throws IOException { 55 long totalRead = 0L; 56 byte[] buffer = new byte[BUFFER_SIZE]; 57 int read; 58 while ((read = source.read(buffer)) > -1) { 59 target.write(buffer, 0, read); 60 totalRead += read; 61 } 62 return totalRead; 63 } 64 65 /** 66 * Reads all characters from an readable and writes them to an appendable. 67 * 68 * @param source the readable to read from 69 * @param target the appendable to write to 70 * 71 * @return the number of characters successfully read and written 72 * 73 * @throws IOException if an I/O error occurs when reading or writing 74 */ 75 public static long copy(Readable source, Appendable target) throws IOException { 76 long totalRead = 0L; 77 CharBuffer buffer = CharBuffer.allocate(BUFFER_SIZE); 78 int read; 79 while ((read = source.read(buffer)) > -1) { 80 buffer.flip(); 81 target.append(buffer, 0, read); 82 totalRead += read; 83 } 84 return totalRead; 85 } 86 }