新IO建立的聊天程序

服务端:

package com.net.scday3;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.Channel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;

public class NServer {
	//用于检测所有Channel的Selector
	private Selector selector =null;
	//编写实现编码解码的字符集对象
	private Charset charset=Charset.forName("UTF-8");

	public void init() throws IOException{
			selector=Selector.open();
			//通过open方法打开一个未绑定的ServerSocketChannel实例
			ServerSocketChannel server=ServerSocketChannel.open();
			InetSocketAddress isa=new InetSocketAddress("127.0.0.1",30000);
			//将该ServerSocketChannel绑定到指定的IP地址
			server.socket().bind(isa);
			//设置ServerSocket以非阻塞方式工作
			server.configureBlocking(false);
			//将Server注册到Selector对象
		    server.register(selector, SelectionKey.OP_ACCEPT);
            while(selector.select()>0){
            	//依次处理selector上的每个已选择的SelectionKey
            	for(SelectionKey sk:selector.selectedKeys()){
            		//从selector上的已选择Key集中删除正在处理的SelctionKey
            			selector.selectedKeys().remove(sk);
            			//如果sk的对应通道包含客户端的连接请求
            			if(sk.isAcceptable()){
            				//调用accept方法接受连接，产生服务器端对应的SocketChannel
            				SocketChannel sc=server.accept();
            				//设置非阻塞模式
            				sc.configureBlocking(false);
            				//将该SocketSchannel也注册到selector
            				sc.register(selector, SelectionKey.OP_READ);
            				//将sk对应的Channel设置成准备接受	其他请求
            				sk.interestOps(SelectionKey.OP_ACCEPT);
            			}
            			//如果sk对应的通过有数据需要读取
            			if(sk.isReadable()){
            				//获取该SelectionKey对应Channel,该Channel中有可读的数据
            				SocketChannel sc=(SocketChannel) sk.channel();
            				//定义准备执行读取数据的ByteBuffer
            				ByteBuffer buff=ByteBuffer.allocate(1024);
            				String content="";
            				//开始读取数据
            			try {
							 while(sc.read(buff)>0){
            					buff.flip();
            					content+=charset.decode(buff);
            				}
							 //打印从该sk对应的Channel读取到的数据
							 System.out.println("===="+content);
							 //将sk对应的Channel设置成准备下一次读取
							 sk.interestOps(SelectionKey.OP_READ);
						}

            			//如果捕捉到该sk对应的Channel出现了异常，即表明该Channel
            			//对应的Client出现了异常，所以从Selector中取消sk的注册

            			catch (Exception e) {
            				//从Selector中删除指定的SelectionKey
            				sk.cancel();
            				if(sk.channel()!=null){
            					sk.channel().close();
            				}
						  }
            		//如果content的长度大于0	,即聊天信息不为空
            			if(content.length()>0){
            				//遍历该selector里注册的所有SelectKey
            				for(SelectionKey key:selector.keys()){
            					//获取该key对应的channel
            					Channel targetChannel=key.channel();
            					//如果该channle是SocketChannle对象
            					if(targetChannel instanceof SocketChannel){
            						//将读到的内容放入该Channel中
            						SocketChannel dest=(SocketChannel)targetChannel;
            						dest.write(charset.encode(content));  //客户端会读取该消息内容
            					}
            				}
            			}
             		}
            	}
            }
		}
	public static void main(String[] args) throws IOException {
		new NServer().init();
	}

}

客户端：

package com.net.scday3;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Scanner;

public class NClient {
	//定义检测SocketChannel的Selector对象
	private  Selector selector=null;
	//定义处理编码和解码的字符集
	private Charset charset=Charset.forName("UTF-8");
	//客户端SocketChannel
	private SocketChannel sc=null;

	public void init() throws IOException{
		selector=Selector.open();
		InetSocketAddress isa=new InetSocketAddress("127.0.0.1",30000);
        //调用open静态方法创建连接到指定主机的SocketChannel
		sc=SocketChannel.open(isa);
		//设置该sc以非阻塞方式工作
		sc.configureBlocking(false);
		//将SocketChannel对象注册到指定Selector
		sc.register(selector, SelectionKey.OP_READ);
		//启动读取服务器端数据的线程
		new ClientThread().start();
		//创建键盘输入流
		Scanner scan=new Scanner(System.in);
		while(scan.hasNextLine()){
			//读取键盘输入
			String line=scan.nextLine();
			//将键盘输入的内容输出到SocketChannel中
			sc.write(charset.encode(line));
		}
	}

	//定义读取服务器端的线程
	private class ClientThread extends Thread{
		@Override
		public void run() {
			try {
				while (selector.select()>0){
					//遍历每个可用IO操作Channel对应的SelectionKey
					for(SelectionKey sk:selector.selectedKeys()){
						//删除正在处理的SelectionKey
						selector.selectedKeys().remove(sk);
						//如果该SeclectionKey对应的Channel有可读的数据
						if(sk.isReadable()){
							//使用NIO读取Channel	中的数据
							SocketChannel sc=(SocketChannel) sk.channel();
							ByteBuffer buff=ByteBuffer.allocate(1024);
							String content="";
							while(sc.read(buff)>0){
								sc.read(buff);
								buff.flip();
								content+=charset.decode(buff);
							}
							//打印输出读取的内容
							System.out.println("聊天信息:"+content);
							//为下一次读取做准备
							sk.interestOps(SelectionKey.OP_READ);
						}
					}
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) throws IOException {
		new NClient().init();
	}
}