Netty网络通信框架及面试题解答

netty

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Netty高性能表现在哪些方面?

1.10线程模型：同步非阻塞，用最少的资源做更多的事。

2、内存零拷贝：尽量减少不必要的内存拷贝，实现了更高效率的传输。

3、内存池设计：申请的内存可以重用，主要指直接内存。内部实现是用一颗二叉查找

树管理内存分配情况。

4、串形化处理读写：避免使用锁带来的性能开销。

5、高性能序列化协议：支持protobuf等高性能序列化协议。

Netty 和Tomcat的区别?

1、作用不同:Tomcat是Servlet容器,可以视为Web服务器,而Netty是异步事件驱动的网

络应用程序框架和工具用于简化网络编程，例如TCP和UDP套接字服务器。

2、协议不同:Tomcat是基于http 协议的Web服务器,而Netty能通过编程自定义各种协议

，因为Netty本身自己能编码/解码字节流，所有Netty可以实现,HTTP服务器FTP服务器、

UDP服务器、RPC服务器、WebSocket 服务器、Redis的Proxy服务器、MySQL的Proxy服务

器等等。

Netty中有那种重要组件?

剩余14页未读，继续阅读

java.net.ConnectException: Connection refused: no further information at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) ~[na:1.8.0_352] at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:716) ~[na:1.8.0_352] at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:337) ~[netty-transport-4.1.87.Final.jar:4.1.87.Final] at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:334) ~[netty-transport-4.1.87.Final.jar:4.1.87.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:776) ~[netty-transport-4.1.87.Final.jar:4.1.87.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724) ~[netty-transport-4.1.87.Final.jar:4.1.87.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650) ~[netty-transport-4.1.87.Final.jar:4.1.87.Final] at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562) ~[netty-transport-4.1.87.Final.jar:4.1.87.Final] at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.87.Final.jar:4.1.87.Final] at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.87.Final.jar:4.1.87.Final] at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.87.Final.jar:4.1.87.Final] at java.lang.Thread.run(Thread.java:750) [na:1.8.0_352]

这个错误通常表示您的Java应用程序无法连接到目标主机或端口。可能有多种原因导致这个问题，比如网络连接问题、目标主机或端口未启动、防火墙或网络代理等。您可以尝试先检查网络连接是否正常，然后再检查目标主机或...

2023-07-14 15:19:01.215 WARN 7308 --- [sson-netty-2-15] io.netty.util.concurrent.DefaultPromise : An exception was thrown by org.redisson.misc.RedissonPromise$$Lambda$888/0x00000008008f7440.operationComplete() java.lang.NullPointerException: null 2023-07-14 15:19:01.216 ERROR 7308 --- [sson-netty-2-15] o.r.c.SentinelConnectionManager : Can't execute SENTINEL commands on /172.24.107.11:26379 org.redisson.client.RedisException: ERR No such master with that name. channel: [id: 0x2d66827d, L:/172.23.9.103:46812 - R:/172.24.107.11:26379] command: (SENTINEL SLAVES), params: [mymaster] at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:365) ~[redisson-3.13.3.jar:3.13.3] at org.redisson.client.handler.CommandDecoder.decodeCommand(CommandDecoder.java:196) ~[redisson-3.13.3.jar:3.13.3] at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:134) ~[redisson-3.13.3.jar:3.13.3] at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:104) ~[redisson-3.13.3.jar:3.13.3] at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:501) ~[netty-codec-4.1.51.Final.jar:4.1.51.Final] at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:366) ~[netty-codec-4.1.51.Final.jar:4.1.51.Final] at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276) ~[netty-codec-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:714) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493) ~[netty-transport-4.1.51.Final.jar:4.1.51.Final] at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) ~[netty-common-4.1.51.Final.jar:4.1.51.Final] at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.51.Final.jar:4.1.51.Final] at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.51.Final.jar:4.1.51.Final] at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na] 解决方法

确保你正确地初始化和使用Redisson，并且相关依赖项和配置都正确设置。你可以仔细检查代码并查找可能导致空指针异常的原因。对于第二个问题，即找不到对应名称的主节点（No such master with that name），可能是...

Caused by: java.lang.ClassNotFoundException: io.netty.channel.sctp.nio.NioSctpServerChannel

这个异常表示在运行期间找不到 io.netty.channel.sctp.nio.NioSctpServerChannel 这个类。这可能是由于以下原因之一导致的： 1. 缺少运行时依赖项：如果您的应用程序使用Maven或Gradle等构建工具，则可能需要将...

unable to create channel from class class io.netty.channel.socket.nio.niosoc

无法从类io.netty.channel.socket.nio.niosoc创建通道。这个错误通常表示在使用Netty框架创建通道时，遇到了问题。出现这个错误的原因可能有很多，下面是一些可能的原因和解决方法： 1. 导入了错误版本的Netty库：...

getway reactor.netty.http.server.HttpServerRequest.hostPort()I

根据您的问题，我猜测您想了解的是关于 `reactor.netty.http.server.HttpServerRequest.hostPort()` 方法的信息。 `hostPort()` 方法是 `HttpServerRequest` 类的一个方法，用于获取请求的主机名和端口号。该方法...

nacos-client 2.0.4 mat分析 com.alibaba.nacos.shaded.io.grpc.netty.shaded.io.netty.buffer.PoolThreadCache内存溢出

您好，针对nacos-client 2.0.4版本中com.alibaba.nacos.shaded.io.grpc.netty.shaded.io.netty.buffer.PoolThreadCache内存溢出问题，建议您进行如下操作： 1. 查看堆转储文件，了解哪些对象占用了大量内存，是否...

com.fmall58.wechatsub.business.bizs.UException at com.fmall58.wechatsub.business.service.PubService.isBindWeChatSub(PubService.java:76) at com.fmall58.wechatsub.business.bizs.PubHelper.isBindWeChatSub(PubHelper.java:125) at com.fmall58.wechatsub.business.bizs.PubHelper.execute(PubHelper.java:38) at com.fmall58.wechatsub.server.handlers.ServerHandler.channelRead(ServerHandler.java:103) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:323) at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:297) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:656) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:591) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:508) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:470) at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:909) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)

这是一个Java堆栈跟踪，看起来是在使用Netty框架进行网络通信时发生了异常。具体来说，是在com.fmall58.wechatsub.business.service.PubService中的第76行发生了异常，该方法调用了...

at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496) at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986) at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ... 1 common frames omittedCaused by: java.lang.IllegalStateException: Only 0 of 1 slaves were synced ... 40 common frames omitted

其中，`<masterip>`和`<masterport>`是主节点的IP地址和端口号。执行完上述命令后，从节点将被设置为只读模式，直到从节点与主节点同步完成。另外，您也可以通过Redis的命令行工具或者Redis客户端监控从节点的...

at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:714)

具体到日志中提到的方法，例如 `invokeChannelRead`、`fireChannelRead`、`read` 等，它们是Netty框架中用于处理读取事件和数据的方法。这部分日志并未提供关于认证错误的具体信息，因此需要结合之前提到的错误...

2023-07-13 09:15:56,872 WARN org.apache.flink.runtime.dispatcher.DispatcherRestEndpoint [] - Unhandled exception java.io.IOException: Connection reset by peer at sun.nio.ch.FileDispatcherImpl.read0(Native Method) ~[?:1.8.0_372] at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39) ~[?:1.8.0_372] at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223) ~[?:1.8.0_372] at sun.nio.ch.IOUtil.read(IOUtil.java:192) ~[?:1.8.0_372] at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:379) ~[?:1.8.0_372] at org.apache.flink.shaded.netty4.io.netty.buffer.PooledByteBuf.setBytes(PooledByteBuf.java:253) ~[flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1132) ~[flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:350) ~[flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:151) [flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719) [flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655) [flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581) [flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493) [flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986) [flink-dist-1.15.3.jar:1.15.3] at org.apache.flink.shaded.netty4.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [flink-dist-1.15.3.jar:1.15.3] at java.lang.Thread.run(Thread.java:750) [?:1.8.0_372]

2. 检查客户端和服务器之间的网络配置，确保没有任何防火墙或路由器设置导致连接被重置。 3. 检查客户端和服务器的超时设置，确保它们足够长，以允许请求得到适当的响应。 4. 如果问题仍然存在，可以尝试增加客户端...

rocketmq no netty_tcnative in java.library.path: [/usr/java/packages/lib, /lib, /usr/lib]

你可以从RocketMQ官方网站或者Maven仓库下载适合你操作系统和Java版本的netty-tcnative二进制文件。 3. 将netty-tcnative的二进制文件复制到Java库路径中。根据错误信息中提供的路径，将netty-tcnative的二进制文件...

Caused by: io.netty.channel.AbstractChannel$AnnotatedConnectException: 拒绝连接: node01/192.168.72.110:7077 Caused by: java.net.ConnectException: 拒绝连接 at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:715) at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:330) at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:334) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:702) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493) at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:748) 23/07/07 22:44:06 ERROR StandaloneSchedulerBackend: Application has been killed. Reason: All masters are unresponsive! Giving up. 23/07/07 22:44:06 WARN StandaloneSchedulerBackend: Application ID is not initialized yet. 23/07/07 22:44:06 INFO Utils: Successfully started service 'org.apache.spark.network.netty.NettyBlockTransferService' on port 45096. 23/07/07 22:44:06 INFO NettyBlockTransferService: Server created on node01:45096 23/07/07 22:44:06 INFO BlockManager: Using org.apache.spark.storage.RandomBlockReplicationPolicy for block replication policy 23/07/07 22:44:06 INFO SparkUI: Stopped Spark web UI at http://node01:4040 23/07/07 22:44:06 INFO BlockManagerMaster: Registering BlockManager BlockManagerId(driver, node01, 45096, None) 23/07/07 22:44:06 INFO StandaloneSchedulerBackend: Shutting down all executors

1. 网络连接问题：请确保您的网络连接正常，以及目标节点的 IP 地址和端口号是否正确。 2. 防火墙配置：检查目标节点的防火墙设置，确保允许与该节点的连接。 3. 资源不足：如果您的应用程序需要分配的资源超过了...

kotlin如何使用netty

import io.netty.bootstrap.ServerBootstrap import io.netty.buffer.ByteBuf import io.netty.buffer.Unpooled import io.netty.channel.ChannelHandlerContext import io.netty.channel....

java netty wss_netty实现websocket客户端（支持wss安全连接）

private class WebSocketClientHandler extends io.netty.channel.SimpleChannelInboundHandler<Object> { @Override protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { ...

io.netty.channel.ChannelOption.TCP_FASTOPEN_CONNECT 是属于哪个依赖包

io.netty.channel.ChannelOption.TCP_FASTOPEN_CONNECT 属于 Netty 库的一部分。它是在 Netty 4.1.17 版本中引入的，因此您需要使用至少这个版本或更高版本的 Netty 来使用它。您可以将以下 Maven 依赖添加到您的...

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Netty网络通信框架及面试题解答

Netty面试题 20道.pdf

无法解析 io.netty:netty-codec:4.1.42.Final

java.lang.nosuchmethoderror: reactor.netty.http.server.httpserverrequest.hos

io.netty:netty-all:4.1.6.Final

reactor.netty.http.client.httpclient.chunkedtransfer(z)lreactor/netty/http/c