Here you can find the source of sendFile(FileChannel fileChannel, SocketChannel socketChannel)
public static void sendFile(FileChannel fileChannel, SocketChannel socketChannel) throws IOException
//package com.java2s; /*/*from w ww .j a v a 2 s. c o m*/ * 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.IOException; import java.nio.channels.FileChannel; import java.nio.channels.SocketChannel; public class Main { public static void sendFile(FileChannel fileChannel, SocketChannel socketChannel) throws IOException { long pos = 0; long fileSize = fileChannel.size(); long remainingBytes = fileSize; long transferredBytes = 0; while ((transferredBytes += fileChannel.transferTo(pos, remainingBytes, socketChannel)) < fileSize) { pos += transferredBytes; remainingBytes -= transferredBytes; } socketChannel.socket().getOutputStream().flush(); } }