Java tutorial
/* * Copyright 2002-2014 the original author or authors. * * Licensed 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 org.springframework.http.client; import java.io.IOException; import java.io.OutputStream; import java.net.URI; import java.util.List; import java.util.Map; import java.util.concurrent.ExecutionException; import io.netty.bootstrap.Bootstrap; import io.netty.buffer.ByteBufOutputStream; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpRequest; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.HttpVersion; import org.springframework.http.HttpHeaders; import org.springframework.http.HttpMethod; import org.springframework.util.concurrent.ListenableFuture; import org.springframework.util.concurrent.SettableListenableFuture; /** * {@link org.springframework.http.client.ClientHttpRequest} implementation that uses * Netty 4 to execute requests. * * <p>Created via the {@link Netty4ClientHttpRequestFactory}. * * @author Arjen Poutsma * @since 4.1.2 */ class Netty4ClientHttpRequest extends AbstractAsyncClientHttpRequest implements ClientHttpRequest { private final Bootstrap bootstrap; private final URI uri; private final HttpMethod method; private final ByteBufOutputStream body; public Netty4ClientHttpRequest(Bootstrap bootstrap, URI uri, HttpMethod method, int maxRequestSize) { this.bootstrap = bootstrap; this.uri = uri; this.method = method; this.body = new ByteBufOutputStream(Unpooled.buffer(maxRequestSize)); } @Override public HttpMethod getMethod() { return this.method; } @Override public URI getURI() { return this.uri; } @Override protected OutputStream getBodyInternal(HttpHeaders headers) throws IOException { return this.body; } @Override protected ListenableFuture<ClientHttpResponse> executeInternal(final HttpHeaders headers) throws IOException { final SettableListenableFuture<ClientHttpResponse> responseFuture = new SettableListenableFuture<ClientHttpResponse>(); ChannelFutureListener connectionListener = new ChannelFutureListener() { @Override public void operationComplete(ChannelFuture future) throws Exception { if (future.isSuccess()) { Channel channel = future.channel(); channel.pipeline().addLast(new RequestExecuteHandler(responseFuture)); FullHttpRequest nettyRequest = createFullHttpRequest(headers); channel.writeAndFlush(nettyRequest); } else { responseFuture.setException(future.cause()); } } }; this.bootstrap.connect(this.uri.getHost(), getPort(this.uri)).addListener(connectionListener); return responseFuture; } @Override public ClientHttpResponse execute() throws IOException { try { return executeAsync().get(); } catch (InterruptedException ex) { throw new IOException(ex.getMessage(), ex); } catch (ExecutionException ex) { if (ex.getCause() instanceof IOException) { throw (IOException) ex.getCause(); } else { throw new IOException(ex.getMessage(), ex); } } } private static int getPort(URI uri) { int port = uri.getPort(); if (port == -1) { if ("http".equalsIgnoreCase(uri.getScheme())) { port = 80; } else if ("https".equalsIgnoreCase(uri.getScheme())) { port = 443; } } return port; } private FullHttpRequest createFullHttpRequest(HttpHeaders headers) { io.netty.handler.codec.http.HttpMethod nettyMethod = io.netty.handler.codec.http.HttpMethod .valueOf(this.method.name()); FullHttpRequest nettyRequest = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, nettyMethod, this.uri.getRawPath(), this.body.buffer()); nettyRequest.headers().set(HttpHeaders.HOST, uri.getHost()); nettyRequest.headers().set(HttpHeaders.CONNECTION, io.netty.handler.codec.http.HttpHeaders.Values.CLOSE); for (Map.Entry<String, List<String>> entry : headers.entrySet()) { nettyRequest.headers().add(entry.getKey(), entry.getValue()); } return nettyRequest; } /** * A SimpleChannelInboundHandler to update the given SettableListenableFuture. */ private static class RequestExecuteHandler extends SimpleChannelInboundHandler<FullHttpResponse> { private final SettableListenableFuture<ClientHttpResponse> responseFuture; public RequestExecuteHandler(SettableListenableFuture<ClientHttpResponse> responseFuture) { this.responseFuture = responseFuture; } @Override protected void channelRead0(ChannelHandlerContext context, FullHttpResponse response) throws Exception { this.responseFuture.set(new Netty4ClientHttpResponse(context, response)); } @Override public void exceptionCaught(ChannelHandlerContext context, Throwable cause) throws Exception { this.responseFuture.setException(cause); } } }