首先，让我解释一下背景：
我必须创建一个客户端，它将发送许多HTTP请求来下载图像。这些请求必须是异步的，因为只要图像完成，它就会被添加到队列然后打印到屏幕。因为图像可能很大并且响应被分块，我的处理程序必须将它聚合到缓冲区中。
所以我按照Netty示例代码（HTTP spoon example）。
目前，我有三个静态Map来存储每个通道的通道ID和缓冲区/块布尔/我的最终对象。
private static final ConcurrentHashMap<Integer, ChannelBuffer> BUFFER_MAP = new ConcurrentHashMap<Integer, ChannelBuffer>();
private static final ConcurrentHashMap<Integer, ImagePack> PACK_MAP = new ConcurrentHashMap<Integer, ImagePack>();
private static final ConcurrentHashMap<Integer, Boolean> CHUNKS_MAP = new ConcurrentHashMap<Integer, Boolean>();
之后，我创建了我的引导程序客户端，并计数到countDown挂起的请求数。当响应图像完成时，最终队列和计数器将传递给我的处理程序。
final ClientBootstrap bootstrap = new ClientBootstrap(
new NioClientSocketChannelFactory(
Executors.newCachedThreadPool(),
Executors.newCachedThreadPool()));
bootstrap.setOption("keepAlive", true);
bootstrap.setOption("tcpNoDelay", true);
bootstrap.setOption("reuseAddress", true);
bootstrap.setOption("connectTimeoutMillis", 30000);
final CountDownLatch latch = new CountDownLatch(downloadList.size()) {
@Override
public void countDown() {
super.countDown();
if (getCount() <= 0) {
try {
queue.put(END_OF_QUEUE);
bootstrap.releaseExternalResources();
} catch (InterruptedException ex) {
LOGGER.log(Level.WARNING, ex.getMessage(), ex);
}
}
}
};
bootstrap.getPipeline().addLast("codec", new HttpClientCodec());
bootstrap.getPipeline().addLast("handler", new TileClientHandler(queue, latch));
之后，我为每个要下载的图像创建一个频道，当频道连接时，将创建并发送请求。主机和端口之前已经被提取过了。
for (final ImagePack pack : downloadList) {
final ChannelFuture future = bootstrap.connect(new InetSocketAddress(host, port));
future.addListener(new ChannelFutureListener() {
public void operationComplete(ChannelFuture cf) throws Exception {
final Channel channel = future.getChannel();
PACK_MAP.put(channel.getId(), pack);
final HttpRequest request = new DefaultHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, pack.url);
request.setHeader(HttpHeaders.Names.HOST, host);
request.setHeader(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.CLOSE);
request.setHeader(HttpHeaders.Names.ACCEPT_ENCODING, HttpHeaders.Values.BYTES);
if (channel.isWritable()) {
channel.write(request);
}
}
});
}
现在，这是我的ChannelHandler，它是一个扩展SimpleChannelUpstreamHandler的内部类。连接频道后，会在BUFFER_MAP和CHUNKS_MAP中创建新条目。 BUFFER_MAP包含处理程序用于聚合来自通道的图像块的所有图像缓冲区，CHUNKS_MAP包含响应chunked布尔值。响应完成后，图像InputSteam将添加到队列中，锁存器倒计时并关闭通道。
private class TileClientHandler extends SimpleChannelUpstreamHandler {
private CancellableQueue<Object> queue;
private CountDownLatch latch;
public TileClientHandler(final CancellableQueue<Object> queue, final CountDownLatch latch) {
this.queue = queue;
this.latch = latch;
}
@Override
public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
if(!BUFFER_MAP.contains(ctx.getChannel().getId())){
BUFFER_MAP.put(ctx.getChannel().getId(), new DynamicChannelBuffer(50000));
}
if(!CHUNKS_MAP.contains(ctx.getChannel().getId())){
CHUNKS_MAP.put(ctx.getChannel().getId(), false);
}
}
@Override
public void writeComplete(ChannelHandlerContext ctx, WriteCompletionEvent e) throws Exception {
super.writeComplete(ctx, e);
if(!BUFFER_MAP.contains(ctx.getChannel().getId())){
BUFFER_MAP.put(ctx.getChannel().getId(), new DynamicChannelBuffer(50000));
}
if(!CHUNKS_MAP.contains(ctx.getChannel().getId())){
CHUNKS_MAP.put(ctx.getChannel().getId(), false);
}
}
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
final Integer channelID = ctx.getChannel().getId();
if (!CHUNKS_MAP.get(channelID)) {
final HttpResponse response = (HttpResponse) e.getMessage();
if (response.isChunked()) {
CHUNKS_MAP.put(channelID, true);
} else {
final ChannelBuffer content = response.getContent();
if (content.readable()) {
final ChannelBuffer buf = BUFFER_MAP.get(channelID);
buf.writeBytes(content);
BUFFER_MAP.put(channelID, buf);
messageCompleted(e);
}
}
} else {
final HttpChunk chunk = (HttpChunk) e.getMessage();
if (chunk.isLast()) {
CHUNKS_MAP.put(channelID, false);
messageCompleted(e);
} else {
final ChannelBuffer buf = BUFFER_MAP.get(channelID);
buf.writeBytes(chunk.getContent());
BUFFER_MAP.put(channelID, buf);
}
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
e.getCause().printStackTrace();
latch.countDown();
e.getChannel().close();
}
private void messageCompleted(MessageEvent e) {
final Integer channelID = e.getChannel().getId();
if (queue.isCancelled()) {
return;
}
try {
final ImagePack p = PACK_MAP.get(channelID);
final ChannelBuffer b = BUFFER_MAP.get(channelID);
p.setBuffer(new ByteArrayInputStream(b.array()));
queue.put(p.getTile());
} catch (Exception ex) {
LOGGER.log(Level.WARNING, ex.getMessage(), ex);
}
latch.countDown();
e.getChannel().close();
}
}
我的问题是，当我执行此代码时，我有以下例外：
java.lang.IllegalArgumentException: invalid version format: 3!}@
at org.jboss.netty.handler.codec.http.HttpVersion.<init>(HttpVersion.java:108)
at org.jboss.netty.handler.codec.http.HttpVersion.valueOf(HttpVersion.java:68)
at org.jboss.netty.handler.codec.http.HttpResponseDecoder.createMessage(HttpResponseDecoder.java:110)
at org.jboss.netty.handler.codec.http.HttpMessageDecoder.decode(HttpMessageDecoder.java:198)
at org.jboss.netty.handler.codec.http.HttpClientCodec$Decoder.decode(HttpClientCodec.java:113)
at org.jboss.netty.handler.codec.http.HttpClientCodec$Decoder.decode(HttpClientCodec.java:101)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.callDecode(ReplayingDecoder.java:470)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.messageReceived(ReplayingDecoder.java:443)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleUpstream(HttpClientCodec.java:77)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:274)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:261)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:351)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:282)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:202)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
java.lang.IllegalArgumentException: invalid version format:
at org.jboss.netty.handler.codec.http.HttpVersion.<init>(HttpVersion.java:108)
at org.jboss.netty.handler.codec.http.HttpVersion.valueOf(HttpVersion.java:68)
at org.jboss.netty.handler.codec.http.HttpResponseDecoder.createMessage(HttpResponseDecoder.java:110)
at org.jboss.netty.handler.codec.http.HttpMessageDecoder.decode(HttpMessageDecoder.java:198)
at org.jboss.netty.handler.codec.http.HttpClientCodec$Decoder.decode(HttpClientCodec.java:113)
at org.jboss.netty.handler.codec.http.HttpClientCodec$Decoder.decode(HttpClientCodec.java:101)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.callDecode(ReplayingDecoder.java:470)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.cleanup(ReplayingDecoder.java:546)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.channelDisconnected(ReplayingDecoder.java:449)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleUpstream(HttpClientCodec.java:77)
at org.jboss.netty.channel.Channels.fireChannelDisconnected(Channels.java:360)
at org.jboss.netty.channel.socket.nio.NioWorker.close(NioWorker.java:595)
at org.jboss.netty.channel.socket.nio.NioClientSocketPipelineSink.eventSunk(NioClientSocketPipelineSink.java:101)
at org.jboss.netty.handler.codec.oneone.OneToOneEncoder.handleDownstream(OneToOneEncoder.java:60)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleDownstream(HttpClientCodec.java:82)
at org.jboss.netty.channel.Channels.close(Channels.java:720)
at org.jboss.netty.channel.AbstractChannel.close(AbstractChannel.java:200)
at org.geotoolkit.client.map.CachedPyramidSet$TileClientHandler.exceptionCaught(CachedPyramidSet.java:515)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:461)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleUpstream(HttpClientCodec.java:77)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:432)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:52)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:274)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:261)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:351)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:282)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:202)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
22 mars 2012 15:27:31 org.jboss.netty.channel.DefaultChannelPipeline
ATTENTION: An exception was thrown by a user handler while handling an exception event ([id: 0x3cd16610, /172.16.30.91:34315 :> tile.openstreetmap.org/193.63.75.98:80] EXCEPTION: java.lang.IllegalArgumentException: invalid version format:
java.lang.IllegalStateException: An Executor cannot be shut down from the thread acquired from itself. Please make sure you are not calling releaseExternalResources() from an I/O worker thread.
at org.jboss.netty.util.internal.ExecutorUtil.terminate(ExecutorUtil.java:71)
at org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory.releaseExternalResources(NioClientSocketChannelFactory.java:171)
at org.jboss.netty.bootstrap.Bootstrap.releaseExternalResources(Bootstrap.java:324)
at org.geotoolkit.client.map.CachedPyramidSet$1.countDown(CachedPyramidSet.java:314)
at org.geotoolkit.client.map.CachedPyramidSet$TileClientHandler.exceptionCaught(CachedPyramidSet.java:514)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:461)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleUpstream(HttpClientCodec.java:77)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:432)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:52)
at org.jboss.netty.channel.Channels.fireChannelDisconnected(Channels.java:360)
at org.jboss.netty.channel.socket.nio.NioWorker.close(NioWorker.java:595)
at org.jboss.netty.channel.socket.nio.NioClientSocketPipelineSink.eventSunk(NioClientSocketPipelineSink.java:101)
at org.jboss.netty.handler.codec.oneone.OneToOneEncoder.handleDownstream(OneToOneEncoder.java:60)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleDownstream(HttpClientCodec.java:82)
at org.jboss.netty.channel.Channels.close(Channels.java:720)
at org.jboss.netty.channel.AbstractChannel.close(AbstractChannel.java:200)
at org.geotoolkit.client.map.CachedPyramidSet$TileClientHandler.exceptionCaught(CachedPyramidSet.java:515)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.exceptionCaught(ReplayingDecoder.java:461)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleUpstream(HttpClientCodec.java:77)
at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:432)
at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:52)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:274)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:261)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:351)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:282)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:202)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
还有一些NPE出现了。
java.lang.NullPointerException
at org.jboss.netty.handler.codec.http.HttpMessageDecoder.skipControlCharacters(HttpMessageDecoder.java:409)
at org.jboss.netty.handler.codec.http.HttpMessageDecoder.decode(HttpMessageDecoder.java:184)
at org.jboss.netty.handler.codec.http.HttpClientCodec$Decoder.decode(HttpClientCodec.java:113)
at org.jboss.netty.handler.codec.http.HttpClientCodec$Decoder.decode(HttpClientCodec.java:101)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.callDecode(ReplayingDecoder.java:470)
at org.jboss.netty.handler.codec.replay.ReplayingDecoder.messageReceived(ReplayingDecoder.java:443)
at org.jboss.netty.handler.codec.http.HttpClientCodec.handleUpstream(HttpClientCodec.java:77)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:274)
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:261)
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:351)
at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:282)
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:202)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
所有这些代码都适用于一个请求，但是当许多请求发送时，一些奇怪的东西会附加到缓冲区。
我在这里缺少什么想法？感谢。
在我的第一个版本中，我为每个请求的图像复制了bootstrap / handler，它工作正常但不是很优化。
答案 0 :(得分：5)
问题是你在所有频道之间共享一个HttpClientCodec。将为所有通道克隆引导程序中指定的默认管道，因此每个通道都会看到每个处理程序的相同实例。 http编解码器是有状态的，因此您可以看到不同响应的效果混合在一起。
最简单的解决方案是将ChannelPipelineFactory传递给引导程序。这将针对每个新通道调用，您可以使用HttpClientCodec的新实例创建管道。没有什么可以阻止你为你创建的每个管道使用相同的TileClientHandler实例，如果这是它的工作方式。
我很好奇。鉴于您同时发出每个请求，在HttpClientCodec上游添加HttpChunkAggregator并让Netty将所有块聚合成单个HttpResponse会不会更容易。然后你只是从那里抓取重新组装的内容？