Java NIO (i)

Java NIO, which features non-blocking, channel multiplexing, greatly improves the efficiency of TCP communications, and because Java NiO has non-blocking features, a single line can be used to manage multiple links based on this feature. The following program demonstrates a simple simulation of the build of a TCP server and client access without using selector:

1, Server class Server.java

Package com.zws.nio.nosel;import java.io.ioexception;import java.net.inetsocketaddress;import  java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;import  com.zws.nio.util.niohelper;public class server extends thread{private  Serversocketchannel sevchn = null;private socketchannel chn = null;private  boolean block = false;private int port;public server (Int port)  { This.port = port;init ();} @Overridepublic  void run ()  {while  (!isinterrupted ())  {try {// The Accept method here is a non-blocking method that returns null without a client link, whether or not a client link is returned. if  ((Chn = sevchn.accept ())  != null)  {string msg = niohelper.read (CHN); System.out.println ("server gets msg:"  + msg);msg =  "Hello client ..."; Niohelper.write (chn, msg); Chn.close ();}  else {//do something else}} catch  (ioexception e)  {e.printstacktrace ();}} /* *  Initialize Serversocketchannel, Socketchannel */private void init ()  {try { Sevchn = serversocketchannel.open (); sevchn.configureblocking (block);//configuration blocking, false: Non-blocking, true: Block Sevchn.socket (). Bind (New inetsocketaddress (port));}  catch  (ioexception e)  {e.printstacktrace ();}} /** *  shut Down Server  */public void close ()  {this.interrupt ();if  (sevChn !=  null) Try {sevchn.close ();}  catch  (ioexception e)  {e.printstacktrace ();}} Public static void main (String[] args)  {Server server = new  Server (9003); Server.start ();//server.close ();}}

2, Client class: Client.java

Package com.zws.nio.nosel;import java.io.ioexception;import java.net.inetsocketaddress;import  java.nio.channels.socketchannel;import com.zws.nio.util.niohelper;public class client  {public static void main (String[] args)  {boolean block = false; Socketchannel chn = null;try {chn = socketchannel.open (); Chn.connect (new  Inetsocketaddress ("localhost",  9003)), chn.configureblocking (block);while  (true)  {//whether to complete the link, non-blocking method. if  (Chn.finishconnect ())  {String msg =  "Hello server ..."; Niohelper.write (chn, msg); Msg = niohelper.read (CHN); System.out.println ("client gets msg:"  + msg);  else {//do something else}}} catch  (ioexception e)  {e.printstacktrace ();}  finally {if  (Chn != null) Try {chn.close ();}  catch  (ioexception e)  {E.printstacktrace ();}}} 

3, Auxiliary class: Niohelper.java

package com.zws.nio.util;import java.io.ioexception;import java.nio.bytebuffer;import  java.nio.channels.socketchannel;public class niohelper {public static final  string charset_utf8 =  "UTF-8";p ublic static void write (SocketChannel chn,  string msg)  throws ioexception {byte[] bts = msg.getbytes (CHARSET_ UTF8);int len = bts.length; Bytebuffer buffer = bytebuffer.allocate (len + 4); Buffer.put (IntegerUtil.toBytes (len)) ;//The first 4 bytes are the message length buffer.put (BTS); Buffer.flip ();while  (buffer.hasremaining ()) chn.write (buffer);} Public static string read (SOCKETCHANNEL CHN)  throws ioexception {string  msg = null;byte[] bts = new byte[4]; Bytebuffer buffer = bytebuffer.allocate (4);while  (chn.read (buffer)  == 0)  {} Buffer.flip (); Buffer.get (Bts, 0, buffer.remaining ()); Int size = integerutil.toint (BTS);buffer =  Bytebuffer.allocate (size);while  (chn.read (buffer)  == 0)  {}buffer.flip ();bts =  New byte[size];buffer.get (Bts, 0, buffer.remaining ()); Msg = new string (BTS, CHARSET_UTF8); return msg;}}

4, Auxiliary class: Integerutil.java

package com.zws.nio.util;public class integerutil {/** *  int into a 4-byte array  *   @param  value *  @return  */public static byte[] tobytes (int value)  {    byte[] bytes = new byte[4];    for   (int i = 0; i < 4; i++)  {         bytes[i] =  (Byte)   (VALUE&NBSP;&GT;&GT;&NBSP;8&NBSP;*&NBSP;I&NBSP;&AMP;&NBSP;0XFF);     }    return bytes;} /** *  byte array conversion int *  @param  bytes *  @return  */public static int  toint (byte[] bytes)  {    int value = 0;     for  (int i = 0; i < bytes.length; i++)  {         byte item = bytes[i];        value +=  (ITEM&NBSP;&AMP;&NBSP;0XFF)  < <  (8 * i);     }    return value;}}

This article is from the "Evan" blog, be sure to keep this source http://wenshengzhu.blog.51cto.com/5151285/1707510

Java NIO (i)