Here you can find the source of copyLarge(Reader input, Writer output)
public static long copyLarge(Reader input, Writer output) throws IOException
//package com.java2s; /**//ww w.jav a2 s .c om * Copyright (c) 2011 Samson Wu * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * */ import java.io.IOException; import java.io.Reader; import java.io.Writer; public class Main { private static final int DEFAULT_BUFFER_SIZE = 1024 * 4; public static long copyLarge(Reader input, Writer output) throws IOException { char[] buffer = new char[DEFAULT_BUFFER_SIZE]; long count = 0; int n = 0; while (-1 != (n = input.read(buffer))) { output.write(buffer, 0, n); count += n; } return count; } }