Java tutorial
//package com.java2s; /* * Copyright (C) 2016 Google Inc. All Rights Reserved. * * 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. */ import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class Main { /** * Reads all bytes from an input stream into a byte array. * Does not close the stream. * * @param in the input stream to read from * @return a byte array containing all the bytes from the stream * @throws IOException if an I/O error occurs */ public static byte[] toByteArray(InputStream in) throws IOException { // Presize the ByteArrayOutputStream since we know how large it will need // to be, unless that value is less than the default ByteArrayOutputStream // size (32). ByteArrayOutputStream out = new ByteArrayOutputStream(Math.max(32, in.available())); copy(in, out); return out.toByteArray(); } /** * Copies all bytes from the input stream to the output stream. * Does not close or flush either stream. * * @param from the input stream to read from * @param to the output stream to write to * @return the number of bytes copied * @throws IOException if an I/O error occurs */ private static long copy(InputStream from, OutputStream to) throws IOException { byte[] buf = new byte[8192]; long total = 0; while (true) { int r = from.read(buf); if (r == -1) { break; } to.write(buf, 0, r); total += r; } return total; } }