运行使用Netty的服务时遇到问题。它启动并正常工作，但只有一次。之后，不接受任何连接（它们会被立即删除）。
我有多个侦听器，每个侦听器只接受ony连接，之后就无法连接到同一个侦听器。
这是我的Listener.java：
public class Listener
{
/* ... */
public void run()
{
// check if there is any sense in running this listener
if (this.address == null) {
this.logger.info("\"{}\" was not enabled for connection, no point to start it.", this.getName());
return;
}
final int maxPacketSize = this.getMaxPacketSize();
final ChannelHandler handler = new DispatcherHandler<ContextType>(this.context, this.dispatcher);
EventLoopGroup acceptors = new NioEventLoopGroup();
EventLoopGroup workers = new NioEventLoopGroup();
try {
// network service configuration
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap
.group(acceptors, workers)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_REUSEADDR, true)
.handler(new LoggingHandler(Listener.class))
.childHandler(new ChannelInitializer<Channel> () {
@Override
public void initChannel(Channel channel)
{
// network service configuration
channel.pipeline().addLast(
new LoggingHandler(handler.getClass()),
new LineBasedFrameDecoder(maxPacketSize),
new StringDecoder(StandardCharsets.UTF_8),
new StringEncoder(StandardCharsets.UTF_8),
handler
);
}
});
// start the server
this.channel = bootstrap.bind(this.address).sync().channel();
this.logger.info("Started."); // (1)
// wait until channel is closed
this.channel.closeFuture().sync();
this.logger.info("Stopped."); // (2)
} catch (InterruptedException error) {
// don't worry - it's what we want in fact
this.logger.error("Interrupted."); // (3)
//CHECKSTYLE:OFF: IllegalCatchCheck
} catch (Throwable error) {
//CHECKSTYLE:ON: IllegalCatchCheck
// this is not expected
this.logger.error("IO connection error: {}.", error.getMessage()); // (4)
} finally {
this.logger.info("Finalizing."); // (5)
this.channel = null;
// close connections
acceptors.shutdownGracefully();
workers.shutdownGracefully();
this.logger.info("Done."); // (6)
}
}
}
DispatcherHandler.java：
public class DispatcherHandler<ContextType extends ContextInterface> extends ChannelInboundHandlerAdapter
{
/* ... */
@Override
public void exceptionCaught(ChannelHandlerContext session, Throwable error)
{
this.logger.error(
"Session ID {}: connection exteption.",
session.name(),
error
);
session.writeAndFlush(new JSONRPC2Response(JSONRPC2Error.INTERNAL_ERROR, null));
session.close();
}
@Override
public void channelRead(ChannelHandlerContext session, Object message)
{
JSONRPC2Response response = null;
try {
// parse the request
JSONRPC2Request request = JSONRPC2Request.parse(message.toString());
// dispatch it
try {
response = this.dispatcher.dispatch(request, this.context);
//CHECKSTYLE:OFF: IllegalCatchCheck
} catch (Throwable error) {
//CHECKSTYLE:ON: IllegalCatchCheck
// we DO WANT to catch all exceptions to avoid listener thread to die
this.logger.error("Internal error.", error);
response = new JSONRPC2Response(
JSONRPC2Error.INTERNAL_ERROR.appendMessage(": " + error.getMessage() + "."),
request.getID()
);
}
} catch (JSONRPC2ParseException error) {
response = new JSONRPC2Response(JSONRPC2Error.PARSE_ERROR, null);
this.logger.error("Could not parse JSON-RPC request.");
}
// send response to client
session.writeAndFlush(response.toJSONString());
}
}
（我知道有些东西可以简化，它是一个仍然可以重现问题的快捷版本）
当我第一次使用nc localhost 6000（示例端口，无论什么）连接到服务器时，一切正常：
客户会话：
rafal.wrzeszcz@devel0:~$ nc -vv localhost 6000
localhost [127.0.0.1] 6000 (?) open
test
{"id":null,"error":{"code":-32700,"message":"JSON parse error"},"jsonrpc":"2.0"}^C
rafal.wrzeszcz@devel0:~$
服务器日志：
10:45:37.036 [nioEventLoopGroup-3-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0xd8fbf0ce, /0:0:0:0:0:0:0:0:6000] RECEIVED: [id: 0xb89181bd, /172.17.0.1:56485 => /172.17.0.2:6000]
10:45:37.056 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb89181bd, /172.17.0.1:56485 => /172.17.0.2:6000] REGISTERED
10:45:37.056 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb89181bd, /172.17.0.1:56485 => /172.17.0.2:6000] ACTIVE
10:45:39.285 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb89181bd, /172.17.0.1:56485 => /172.17.0.2:6000] RECEIVED: test
10:45:39.293 [nioEventLoopGroup-11-1] ERROR pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - Could not parse JSON-RPC request.
10:45:39.294 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb89181bd, /172.17.0.1:56485 => /172.17.0.2:6000] WRITE: {"id":null,"error":{"code":-32700,"message":"JSON parse error"},"jsonrpc":"2.0"}
10:45:39.297 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb89181bd, /172.17.0.1:56485 => /172.17.0.2:6000] FLUSH
10:45:40.066 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb89181bd, /172.17.0.1:56485 :> /172.17.0.2:6000] INACTIVE
10:45:40.067 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb89181bd, /172.17.0.1:56485 :> /172.17.0.2:6000] UNREGISTERED
（不要担心JSON-RPC错误，它的逻辑错误，正确的请求和响应它的工作方式完全相同）
但在关闭客户端连接后，再也无法连接。
客户会话：
rafal.wrzeszcz@devel0:~$ nc -vv localhost 6000
localhost [127.0.0.1] 6000 (x11) open
sent 0, rcvd 0
rafal.wrzeszcz@devel0:~$
服务器日志：
10:45:40.539 [nioEventLoopGroup-3-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0xd8fbf0ce, /0:0:0:0:0:0:0:0:6000] RECEIVED: [id: 0x9e3dc0b1, /172.17.0.1:56487 => /172.17.0.2:6000]
10:45:40.545 [nioEventLoopGroup-11-2] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x9e3dc0b1, /172.17.0.1:56487 :> /172.17.0.2:6000] INACTIVE
10:45:40.547 [nioEventLoopGroup-11-2] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x9e3dc0b1, /172.17.0.1:56487 :> /172.17.0.2:6000] UNREGISTERED
- 编辑 -
Netty版本：4.0.33.Final
- 编辑2 -
只要连接处于活动状态，服务器就可以正常工作 - 我能够连续交换请求/响应，直到我关闭连接。
不要被IP地址混淆，它是转发到Docker的本地端口，应用程序在这里启动。它应该不是问题，我有 Apache MINA 应用程序以相同的方式运行，并尝试将其移植到Netty。
- 编辑3 -
rafal.wrzeszcz@devel0:~$ nc -vv localhost 6000
localhost [127.0.0.1] 6000 (x11) open
test
{"id":null,"error":{"code":-32700,"message":"JSON parse error"},"jsonrpc":"2.0"}test
{"id":null,"error":{"code":-32700,"message":"JSON parse error"},"jsonrpc":"2.0"}^C sent 10, rcvd 160
rafal.wrzeszcz@devel0:~$ nc -vv localhost 6000
localhost [127.0.0.1] 6000 (x11) open
sent 0, rcvd 0
一切都是一样的，在我按[CTRL] + [C]：
12:05:53.720 [chilldev.pl-frontend] INFO pl.chilldev.commons.jsonrpc.daemon.Listener - Started.
12:05:58.075 [nioEventLoopGroup-6-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0x7cbe3265, /0:0:0:0:0:0:0:0:6000] RECEIVED: [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000]
12:05:58.095 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] REGISTERED
12:05:58.096 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] ACTIVE
12:06:02.122 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] RECEIVED: test
12:06:02.129 [nioEventLoopGroup-11-1] ERROR pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - Could not parse JSON-RPC request.
12:06:02.129 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] WRITE: {"id":null,"error":{"code":-32700,"message":"JSON parse error"},"jsonrpc":"2.0"}
12:06:02.132 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] FLUSH
12:06:03.414 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] RECEIVED: test
12:06:03.415 [nioEventLoopGroup-11-1] ERROR pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - Could not parse JSON-RPC request.
12:06:03.416 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] WRITE: {"id":null,"error":{"code":-32700,"message":"JSON parse error"},"jsonrpc":"2.0"}
12:06:03.416 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 => /172.17.0.2:6000] FLUSH
12:06:04.091 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 :> /172.17.0.2:6000] INACTIVE
12:06:04.091 [nioEventLoopGroup-11-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0xb284a0b1, /172.17.0.1:57853 :> /172.17.0.2:6000] UNREGISTERED
12:06:07.923 [nioEventLoopGroup-6-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0x7cbe3265, /0:0:0:0:0:0:0:0:6000] RECEIVED: [id: 0x0def7d2a, /172.17.0.1:57856 => /172.17.0.2:6000]
12:06:07.932 [nioEventLoopGroup-11-2] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0def7d2a, /172.17.0.1:57856 :> /172.17.0.2:6000] INACTIVE
12:06:07.933 [nioEventLoopGroup-11-2] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0def7d2a, /172.17.0.1:57856 :> /172.17.0.2:6000] UNREGISTERED
^C12:08:25.329 [Thread-14] INFO pl.chilldev.commons.jsonrpc.daemon.AbstractApplication - Stopping…
12:08:25.335 [nioEventLoopGroup-6-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0x7cbe3265, /0:0:0:0:0:0:0:0:6000] CLOSE()
12:08:25.337 [chilldev.pl-frontend] INFO pl.chilldev.commons.jsonrpc.daemon.Listener - Stopped.
12:08:25.337 [nioEventLoopGroup-6-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0x7cbe3265, /0:0:0:0:0:0:0:0:6000] UNREGISTERED
12:08:25.337 [chilldev.pl-frontend] INFO pl.chilldev.commons.jsonrpc.daemon.Listener - Finalizing.
12:08:25.345 [chilldev.pl-frontend] INFO pl.chilldev.commons.jsonrpc.daemon.Listener - Done.
[CTRL] + [C]）之前，不会记录- 编辑4 -
LoggingHandler为第一个处理程序12:18:52.396 [nioEventLoopGroup-3-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0xbec73d3f, /0:0:0:0:0:0:0:0:6000] RECEIVED: [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000]
12:18:52.432 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] REGISTERED
12:18:52.435 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] ACTIVE
12:18:53.479 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] RECEIVED: 5B
+-------------------------------------------------+
| 0 1 2 3 4 5 6 7 8 9 a b c d e f |
+--------+-------------------------------------------------+----------------+
|00000000| 74 65 73 74 0a |test. |
+--------+-------------------------------------------------+----------------+
12:18:53.495 [nioEventLoopGroup-9-1] ERROR pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - Could not parse JSON-RPC request.
12:18:53.497 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] WRITE: 80B
+-------------------------------------------------+
| 0 1 2 3 4 5 6 7 8 9 a b c d e f |
+--------+-------------------------------------------------+----------------+
|00000000| 7b 22 69 64 22 3a 6e 75 6c 6c 2c 22 65 72 72 6f |{"id":null,"erro|
|00000010| 72 22 3a 7b 22 63 6f 64 65 22 3a 2d 33 32 37 30 |r":{"code":-3270|
|00000020| 30 2c 22 6d 65 73 73 61 67 65 22 3a 22 4a 53 4f |0,"message":"JSO|
|00000030| 4e 20 70 61 72 73 65 20 65 72 72 6f 72 22 7d 2c |N parse error"},|
|00000040| 22 6a 73 6f 6e 72 70 63 22 3a 22 32 2e 30 22 7d |"jsonrpc":"2.0"}|
+--------+-------------------------------------------------+----------------+
12:18:53.499 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] FLUSH
12:18:54.369 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] RECEIVED: 5B
+-------------------------------------------------+
| 0 1 2 3 4 5 6 7 8 9 a b c d e f |
+--------+-------------------------------------------------+----------------+
|00000000| 74 65 73 74 0a |test. |
+--------+-------------------------------------------------+----------------+
12:18:54.370 [nioEventLoopGroup-9-1] ERROR pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - Could not parse JSON-RPC request.
12:18:54.372 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] WRITE: 80B
+-------------------------------------------------+
| 0 1 2 3 4 5 6 7 8 9 a b c d e f |
+--------+-------------------------------------------------+----------------+
|00000000| 7b 22 69 64 22 3a 6e 75 6c 6c 2c 22 65 72 72 6f |{"id":null,"erro|
|00000010| 72 22 3a 7b 22 63 6f 64 65 22 3a 2d 33 32 37 30 |r":{"code":-3270|
|00000020| 30 2c 22 6d 65 73 73 61 67 65 22 3a 22 4a 53 4f |0,"message":"JSO|
|00000030| 4e 20 70 61 72 73 65 20 65 72 72 6f 72 22 7d 2c |N parse error"},|
|00000040| 22 6a 73 6f 6e 72 70 63 22 3a 22 32 2e 30 22 7d |"jsonrpc":"2.0"}|
+--------+-------------------------------------------------+----------------+
12:18:54.372 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 => /172.17.0.2:6000] FLUSH
12:18:55.174 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 :> /172.17.0.2:6000] INACTIVE
12:18:55.181 [nioEventLoopGroup-9-1] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x0c8be37b, /172.17.0.1:58020 :> /172.17.0.2:6000] UNREGISTERED
12:19:01.203 [nioEventLoopGroup-3-1] DEBUG pl.chilldev.commons.jsonrpc.daemon.Listener - [id: 0xbec73d3f, /0:0:0:0:0:0:0:0:6000] RECEIVED: [id: 0x9fa99c9e, /172.17.0.1:58022 => /172.17.0.2:6000]
12:19:01.210 [nioEventLoopGroup-9-2] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x9fa99c9e, /172.17.0.1:58022 :> /172.17.0.2:6000] INACTIVE
12:19:01.210 [nioEventLoopGroup-9-2] DEBUG pl.chilldev.commons.jsonrpc.netty.DispatcherHandler - [id: 0x9fa99c9e, /172.17.0.1:58022 :> /172.17.0.2:6000] UNREGISTERED
答案 0 :(得分：3)
好的，想通了。 @zapl添加其他日志的想法促使我为io.netty添加了记录器。这是下次连接尝试后发生的事情：
12:25:53.007 [nioEventLoopGroup-8-2] WARN io.netty.channel.ChannelInitializer - Failed to initialize a channel. Closing: [id: 0xed038b64, /172.17.0.1:58276 => /172.17.0.2:6000]
io.netty.channel.ChannelPipelineException: pl.chilldev.commons.jsonrpc.netty.DispatcherHandler is not a @Sharable handler, so can't be added or removed multiple times.
我认为它足够清楚;）。
答案 1 :(得分：0)
感谢Rafał为您answer。
我还想分享其他信息，如果您使用的是非Sharable处理程序，则每次将其添加到管道时都需要创建一个新实例。
public static @interface ChannelHandler.Sharable
表示带注释的ChannelHandler的相同实例可以 在没有竞赛的情况下多次添加到一个或多个ChannelPipelines 条件。
如果未指定此注释，则必须创建新的处理程序 每次将它添加到管道时，因为它已取消共享 状态，如成员变量。