Java tutorial
/* * Copyright 2016 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 me.netty.http.handler; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufUtil; import io.netty.channel.ChannelDuplexHandler; import io.netty.channel.ChannelHandler.Sharable; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.http2.*; import io.netty.util.CharsetUtil; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import static io.netty.buffer.Unpooled.copiedBuffer; import static io.netty.buffer.Unpooled.unreleasableBuffer; import static io.netty.handler.codec.http.HttpResponseStatus.OK; /** * A simple handler that responds with the message "Hello World!". * * <p>This example is making use of the "multiplexing" http2 API, where streams are mapped to child * Channels. This API is very experimental and incomplete. */ @Sharable public class HelloWorldHttp2Handler extends ChannelDuplexHandler { private static Log logger = LogFactory.getLog(HelloWorldHttp2Handler.class); static final ByteBuf RESPONSE_BYTES = unreleasableBuffer(copiedBuffer("Hello World", CharsetUtil.UTF_8)); @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { super.exceptionCaught(ctx, cause); cause.printStackTrace(); ctx.close(); } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { if (msg instanceof Http2HeadersFrame) { onHeadersRead(ctx, (Http2HeadersFrame) msg); } else if (msg instanceof Http2DataFrame) { onDataRead(ctx, (Http2DataFrame) msg); } else { super.channelRead(ctx, msg); } } /** * If receive a frame with end-of-stream set, send a pre-canned response. */ public void onDataRead(ChannelHandlerContext ctx, Http2DataFrame data) throws Exception { if (data.isEndStream()) { sendResponse(ctx, data.content().retain()); } logger.debug("get body stream id is : " + data.streamId()); } /** * If receive a frame with end-of-stream set, send a pre-canned response. */ public void onHeadersRead(ChannelHandlerContext ctx, Http2HeadersFrame headers) throws Exception { if (headers.isEndStream()) { ByteBuf content = ctx.alloc().buffer(); content.writeBytes(RESPONSE_BYTES.duplicate()); ByteBufUtil.writeAscii(content, " - via HTTP/2"); sendResponse(ctx, content); } logger.debug("get header stream id is : " + headers.streamId()); } /** * Sends a "Hello World" DATA frame to the client. */ private void sendResponse(ChannelHandlerContext ctx, ByteBuf payload) { // Send a frame for the response status Http2Headers headers = new DefaultHttp2Headers().status(OK.codeAsText()); ctx.write(new DefaultHttp2HeadersFrame(headers)); ctx.writeAndFlush(new DefaultHttp2DataFrame(payload, true)); } }