Java tutorial
//package com.java2s; /* * 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. */ import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.Reader; public class Main { private static final int EOF = -1; /** * Compare the contents of two Streams to determine if they are equal or * not. * <p/> * This method buffers the input internally using * <code>BufferedInputStream</code> if they are not already buffered. * * @param input1 the first stream * @param input2 the second stream * @return true if the content of the streams are equal or they both don't * exist, false otherwise * @throws NullPointerException if either input is null * @throws IOException if an I/O error occurs */ public static boolean contentEquals(InputStream input1, InputStream input2) throws IOException { if (!(input1 instanceof BufferedInputStream)) { input1 = new BufferedInputStream(input1); } if (!(input2 instanceof BufferedInputStream)) { input2 = new BufferedInputStream(input2); } int ch = input1.read(); while (EOF != ch) { int ch2 = input2.read(); if (ch != ch2) { return false; } ch = input1.read(); } int ch2 = input2.read(); return ch2 == EOF; } /** * Compare the contents of two Readers to determine if they are equal or * not. * <p/> * This method buffers the input internally using * <code>BufferedReader</code> if they are not already buffered. * * @param input1 the first reader * @param input2 the second reader * @return true if the content of the readers are equal or they both don't * exist, false otherwise * @throws NullPointerException if either input is null * @throws IOException if an I/O error occurs * @since 1.1 */ public static boolean contentEquals(Reader input1, Reader input2) throws IOException { input1 = toBufferedReader(input1); input2 = toBufferedReader(input2); int ch = input1.read(); while (EOF != ch) { int ch2 = input2.read(); if (ch != ch2) { return false; } ch = input1.read(); } int ch2 = input2.read(); return ch2 == EOF; } /** * Read characters from an input character stream. * This implementation guarantees that it will read as many characters * as possible before giving up; this may not always be the case for * subclasses of {@link Reader}. * * @param input where to read input from * @param buffer destination * @param offset inital offset into buffer * @param length length to read, must be >= 0 * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs * @since 2.2 */ public static int read(Reader input, char[] buffer, int offset, int length) throws IOException { if (length < 0) { throw new IllegalArgumentException("Length must not be negative: " + length); } int remaining = length; while (remaining > 0) { int location = length - remaining; int count = input.read(buffer, offset + location, remaining); if (EOF == count) { // EOF break; } remaining -= count; } return length - remaining; } /** * Read characters from an input character stream. * This implementation guarantees that it will read as many characters * as possible before giving up; this may not always be the case for * subclasses of {@link Reader}. * * @param input where to read input from * @param buffer destination * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs * @since 2.2 */ public static int read(Reader input, char[] buffer) throws IOException { return read(input, buffer, 0, buffer.length); } /** * Read bytes from an input stream. * This implementation guarantees that it will read as many bytes * as possible before giving up; this may not always be the case for * subclasses of {@link InputStream}. * * @param input where to read input from * @param buffer destination * @param offset inital offset into buffer * @param length length to read, must be >= 0 * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs * @since 2.2 */ public static int read(InputStream input, byte[] buffer, int offset, int length) throws IOException { if (length < 0) { throw new IllegalArgumentException("Length must not be negative: " + length); } int remaining = length; while (remaining > 0) { int location = length - remaining; int count = input.read(buffer, offset + location, remaining); if (EOF == count) { // EOF break; } remaining -= count; } return length - remaining; } /** * Read bytes from an input stream. * This implementation guarantees that it will read as many bytes * as possible before giving up; this may not always be the case for * subclasses of {@link InputStream}. * * @param input where to read input from * @param buffer destination * @return actual length read; may be less than requested if EOF was reached * @throws IOException if a read error occurs * @since 2.2 */ public static int read(InputStream input, byte[] buffer) throws IOException { return read(input, buffer, 0, buffer.length); } /** * Returns the given reader if it is a {@link BufferedReader}, otherwise creates a toBufferedReader for the given * reader. * * @param reader the reader to wrap or return * @return the given reader or a new {@link BufferedReader} for the given reader * @since 2.2 */ public static BufferedReader toBufferedReader(Reader reader) { return reader instanceof BufferedReader ? (BufferedReader) reader : new BufferedReader(reader); } }