如何在java中使用Netty中的channelhandler来处理String和HttpRequest?

Question

我想处理两个不同的客户端。一种是发送字符串数据包的简单 tcp 客户端。另一个是发送httprequest msg的http客户端。我是 Netty 的初学者，我不知道管道中的处理程序是如何流动的。

这是我的服务器编码：

public class TCPServer {
int port;
public static void main(String[] args) {
new TCPServer().start();
}
public void start() {
port = 1222;
EventLoopGroup producer = new NioEventLoopGroup();
EventLoopGroup consumer = new NioEventLoopGroup();
try {
ServerBootstrap bootstrap = new ServerBootstrap()
.option(ChannelOption.SO_BACKLOG, 1024)
.group(producer, consumer)//separate event loop groups to handle for parent and child for handling all chanel events
.channel(NioServerSocketChannel.class)//select type of chanel
.handler(new LoggingHandler(LogLevel.INFO))
.childHandler(new ServerAdapterInitializer());//configure chanel pipeline
System.out.println("Server started");// configuring server channel
bootstrap.bind(port).sync().channel().closeFuture().sync();//start the server and Wait until the server socket is closed. Thread gets blocked. 
} catch (Exception e) {
e.printStackTrace();
} finally {
producer.shutdownGracefully();
consumer.shutdownGracefully();
}
}
}

这是我的服务器初始值设定项：

<pre>public class ServerAdapterInitializer extends ChannelInitializer<SocketChannel> {//special chanel handler configures registered chanel pipeline
@Override
protected void initChannel(SocketChannel channel) throws Exception {//this method is called once the chanel was registered
ChannelPipeline pipeline = channel.pipeline();
pipeline.addLast("decoder", new StringDecoder());//chanel inbound handler
pipeline.addLast("encoder", new StringEncoder());
pipeline.addLast("handler", new TCPServerHandler());
}
}

这是我处理httprequest和字符串的处理程序。但是我的处理程序从不处理 httprequest 数据包。

class TCPServerHandler extends SimpleChannelInboundHandler<Object> {
private static final byte[] CONTENT = { 'H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd' };
private static final ChannelGroup channels = new DefaultChannelGroup("tasks", GlobalEventExecutor.INSTANCE);                                                               
@Override
public void channelRead0(ChannelHandlerContext ctx, Object msg)
throws Exception {       
if (msg instanceof HttpRequest) {
System.out.println("http request");
HttpRequest req = (HttpRequest) msg;
boolean keepAlive = HttpUtil.isKeepAlive(req);
FullHttpResponse response = new DefaultFullHttpResponse(req.protocolVersion(), OK,Unpooled.wrappedBuffer(CONTENT));
response.headers()
.set(CONTENT_TYPE, TEXT_PLAIN)
.setInt(CONTENT_LENGTH, response.content().readableBytes());
if (keepAlive) {
if (!req.protocolVersion().isKeepAliveDefault()) {
response.headers().set(CONNECTION, KEEP_ALIVE);
}
} else {
// Tell the client we're going to close the connection.
response.headers().set(CONNECTION, CLOSE);
}
ChannelFuture f = ctx.write(response);
if (!keepAlive) {
f.addListener(ChannelFutureListener.CLOSE);
}
}
if(msg instanceof String){
System.out.println("String request");
String arg1=(String)msg;
Channel currentChannel = ctx.channel();
if(arg1.equals("quit")){
System.out.println("[INFO] - " + currentChannel.remoteAddress() + " is quitting... ");
}else{
System.out.println("[INFO] - " + currentChannel.remoteAddress() + " - "+ arg1);
currentChannel.writeAndFlush("Server Said Hii "+ arg1);
}
}
}
}

Answer 1

我认为不可能配置相同的服务器引导程序来处理HTTP请求和原始字符串消息。您需要两个服务器引导程序(一个用于 HTTP，一个用于字符串消息(，每个引导程序都有自己的管道。你已经有用于字符串消息处理的解码器/编码器。

EventLoopGroup producer = new NioEventLoopGroup();
EventLoopGroup consumer = new NioEventLoopGroup();
ServerBootstrap httpSb = new ServerBootstrap();
ServerBootstrap strSb  = new ServerBootstrap();
httpSb.group(producer, consumer).bind(<port for http>).<other methods>...
strSb.group(producer, consumer).bind(<port for strings>).<other methods>...

对于 HTTP，您需要添加处理程序HttpServerCodec和HttpObjectAggregator，以便能够从通道读取FullHttpRequest并将FullHttpResponse写入通道。

(聚合器是可选的，它可以帮助您避免将碎片化的传入 HTTP 数据合并为单个(完整(HTTP 请求以及将组合(完整(HTTP 响应写入通道的任务(

在 HTTP 的引导程序中：

ch.pipeline().addLast("httpcodec"     , new HttpServerCodec());
ch.pipeline().addLast("httpaggregator", new HttpObjectAggregator(512 * 1024));
ch.pipeline().addLast("yourhandler"   , new YourHttpRequestHandler());

用于FullHttpRequest处理的示例处理程序：

public class YourHttpRequestHandler extends ChannelInboundHandlerAdapter  {

@Override
public void channelRead(ChannelHandlerContext ctx, Object msg_arg) 
{
FullHttpRequest msg = (FullHttpRequest)msg_arg;
System.out.println("URI: " + msg.getUri());
System.out.println("method: " + msg.getMethod().toString());
System.out.println("protocol version: " + msg.getProtocolVersion()); 
System.out.println("header1: " + msg.headers().get("header1"));
System.out.println("header2: " + msg.headers().get("header2"));
System.out.println("header3: " + msg.headers().get("header3"));
System.out.println("content: " + msg.content().toString(CharsetUtil.UTF_8));
}//end read
}//end handler