Java tutorial
/* * Copyright 2012 The Netty Project * * The Netty Project 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. */ package io.aos.netty5.filetransfer; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelOption; import io.netty.channel.DefaultFileRegion; import io.netty.channel.EventLoopGroup; import io.netty.channel.FileRegion; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioServerSocketChannel; import io.netty.handler.codec.LineBasedFrameDecoder; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; import io.netty.handler.logging.LogLevel; import io.netty.handler.logging.LoggingHandler; import io.netty.util.CharsetUtil; import java.io.File; import java.io.FileInputStream; /** * Server that accept the path of a file an echo back its content. */ public class FileServer { private final int port; public FileServer(int port) { this.port = port; } public void run() throws Exception { // Configure the server. EventLoopGroup parentGroup = new NioEventLoopGroup(); EventLoopGroup childGroup = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); b.group(parentGroup, childGroup).channel(NioServerSocketChannel.class) .option(ChannelOption.SO_BACKLOG, 100).handler(new LoggingHandler(LogLevel.INFO)) .childHandler(new ChannelInitializer<SocketChannel>() { @Override public void initChannel(SocketChannel ch) throws Exception { ch.pipeline().addLast(new StringEncoder(CharsetUtil.UTF_8), new LineBasedFrameDecoder(8192), new StringDecoder(CharsetUtil.UTF_8), new FileHandler()); } }); // Start the server. ChannelFuture f = b.bind(port).sync(); // Wait until the server socket is closed. f.channel().closeFuture().sync(); } finally { // Shut down all event loops to terminate all threads. parentGroup.shutdownGracefully(); childGroup.shutdownGracefully(); } } public static void main(String[] args) throws Exception { int port; if (args.length > 0) { port = Integer.parseInt(args[0]); } else { port = 8080; } new FileServer(port).run(); } private static final class FileHandler extends SimpleChannelInboundHandler<String> { @Override public void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception { File file = new File(msg); if (file.exists()) { if (!file.isFile()) { ctx.writeAndFlush("Not a file: " + file + '\n'); return; } ctx.write(file + " " + file.length() + '\n'); FileInputStream fis = new FileInputStream(file); FileRegion region = new DefaultFileRegion(fis.getChannel(), 0, file.length()); ctx.write(region); ctx.writeAndFlush("\n"); fis.close(); } else { ctx.writeAndFlush("File not found: " + file + '\n'); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } } }