First Netty Program

This is I just started to learn Netty wrote the first demo, was prepared to follow the "Netty authoritative guide" of the introduction of the demo to knock aside, until I go to download the jar package to build the environment only to find that Netty No 5.x version, now the highest 4.1.9. A face Meng forced me a search just know Netty from 5.x back to 4.x, the specific reason is unclear. 4.x and 5.x, after all, a large version, the middle of a variety of similarities and differences is not my small white can now understand, or according to the official demo come. The following example is a reference to the demo in the official website guide, the approximate logic is that the client requests server time and print to the server.

Service-Side code:

1  Public classTimeserverhandlerextendschannelinboundhandleradapter{2     3     /**4 * Each incoming message is called5      * */6 @Override7      Public voidChannelread (Channelhandlercontext ctx, Object msg)throwsexception{8Bytebuf buf =(BYTEBUF) msg;9         Try{Ten             byte[] req =New byte[Buf.readablebytes ()]; One buf.readbytes (req); AString BODY =NewString (req, "UTF-8"); -SYSTEM.OUT.PRINTLN ("The server received the request:" +body); -String time = "Query time?". Equals (body)?NewDate (). toString (): "Fail"; theBytebuf resp =Unpooled.copiedbuffer (Time.getbytes ()); - Ctx.write (resp); -}finally{ - buf.release (); +         } -     } +      A     //notifies Channelinboundhandleradapter that the last call to Channelread () is the last message in the current bulk read.  at @Override -      Public voidChannelreadcomplete (Channelhandlercontext ctx) { -         /** - * Ctx.write (RESP) is writing information to the message queue, rather than writing it every time write Socketchannel - * Ctx.flush () is the message sent in the queue to write the information in Socketchannel sent to the other side, - * Ctx.writeandflush (RESP) write directly to Socketchannel in          * */ - Ctx.flush (); to     } +      -     //exceptions that occur during processing the @Override *      Public voidexceptioncaught (Channelhandlercontext ctx, throwable cause) { $ cause.printstacktrace ();Panax Notoginseng ctx.close (); -     } the      +}

1  Public classTimeserver {2      Public voidBindintPortthrowsexception{3         //The NIO thread group, which is designed to handle network events, is essentially a reactor thread group. 4Eventloopgroup Bosser =NewNioeventloopgroup ();//connections for server-side accept clients5Eventloopgroup worker =NewNioeventloopgroup ();//network Read and write for Socketchannel6         7         Try {8Serverbootstrap boot =NewServerbootstrap ();//Start the secondary startup class on the NIO server to reduce the complexity of the development. 9             Ten Boot.group (Bosser, worker) One. Channel (Nioserversocketchannel.class) A. option (Channeloption.so_backlog, 1024)//Configuring TCP Parameters -. Childhandler (NewChannelinitializer<socketchannel> () {//used to process network IO events (logging, encoding of messages) - @Override the                 protected voidInitchannel (Socketchannel ch)throwsException { -Ch.pipeline (). AddLast (NewTimeserverhandler ()); -                 } -             }); +              -Channelfuture CF = Boot.bind (port). sync ();//asynchronously binds the server, calling the sync () method to block the wait until the binding is complete.  +Cf.channel (). Closefuture (). sync ();//gets the channelfuture and blocks the current thread until it finishes.  A}finally{ atBosser.shutdowngracefully ();//Release All Resources - worker.shutdowngracefully (); -         } -          -     } -      in      -      Public Static voidMain (string[] args) { to         intPort = 8080; +         Try { -             Newtimeserver (). bind (port); the}Catch(Exception e) { * e.printstacktrace (); $         }Panax Notoginseng     } -}

Client code:

1  Public classTimeclienthandlerextendschannelinboundhandleradapter{2     3     //will be called after the connection to the server has been established4 @Override5      Public voidchannelactive (Channelhandlercontext ctx) {6         byte[] req = "Query time?". GetBytes ();7Bytebuf Firstmessage =Unpooled.buffer (req.length);8 firstmessage.writebytes (req);9 Ctx.writeandflush (firstmessage);Ten     } One      A     //called when a message is received from the server - @Override -      Public voidChannelread (Channelhandlercontext ctx, Object msg)throwsexception{ theBytebuf buf =(BYTEBUF) msg; -         byte[] resp =New byte[Buf.readablebytes ()]; - buf.readbytes (resp); -String str =NewString (resp, "UTF-8"); +SYSTEM.OUT.PRINTLN ("Server time:" +str); -     } +      A @Override at      Public voidChannelreadcomplete (Channelhandlercontext ctx) { - Ctx.flush (); -     } -   -     //exceptions that occur during processing - @Override in      Public voidexceptioncaught (Channelhandlercontext ctx, throwable cause) { - cause.printstacktrace (); to ctx.close (); +     } -        the}

 Public classtimeclient { Public voidConnect (String Host,intPortthrowsexception{Eventloopgroup Group=NewNioeventloopgroup (); Try{Bootstrap boot=NewBootstrap (); Boot.group (Group). Channel (Niosocketchannel.class). Option (Channeloption.tcp_nodelay,true). Handler (NewChannelinitializer<socketchannel>() {@Overrideprotected voidInitchannel (Socketchannel ch)throwsException {ch.pipeline (). AddLast (NewTimeclienthandler ());                        }                            }); Channelfuture CF=Boot.connect (host, port). sync ();        Cf.channel (). Closefuture (). sync (); }finally{group.shutdowngracefully (); }    }         Public Static voidMain (string[] args) {FinalString host = "127.0.0.1"; Final intPort = 8080; Try {            Newtimeclient (). Connect (host, port); } Catch(Exception e) {System.out.println ("Client" + Thread.CurrentThread (). GetId () + "Request Exception"); }                    }}

To run the code:

The starter demo is complete, and the next step is to revise it on the demo, and I'll record the following code.

First Netty Program