Java tutorial
/* * Copyright 2014 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.file; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.DefaultFileRegion; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.ssl.SslHandler; import io.netty.handler.stream.ChunkedFile; import java.io.RandomAccessFile; public class FileServerHandler extends SimpleChannelInboundHandler<String> { @Override public void channelActive(ChannelHandlerContext ctx) { ctx.writeAndFlush("HELO: Type the path of the file to retrieve.\n"); } @Override public void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception { RandomAccessFile raf = null; long length = -1; try { raf = new RandomAccessFile(msg, "r"); length = raf.length(); } catch (Exception e) { ctx.writeAndFlush("ERR: " + e.getClass().getSimpleName() + ": " + e.getMessage() + '\n'); return; } finally { if (length < 0 && raf != null) { raf.close(); } } ctx.write("OK: " + raf.length() + '\n'); if (ctx.pipeline().get(SslHandler.class) == null) { // SSL not enabled - can use zero-copy file transfer. ctx.write(new DefaultFileRegion(raf.getChannel(), 0, length)); } else { // SSL enabled - cannot use zero-copy file transfer. ctx.write(new ChunkedFile(raf)); } ctx.writeAndFlush("\n"); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); if (ctx.channel().isActive()) { ctx.writeAndFlush("ERR: " + cause.getClass().getSimpleName() + ": " + cause.getMessage() + '\n') .addListener(ChannelFutureListener.CLOSE); } } }