基于NIO实现非阻塞Socket编程（二）

三、应用范例

   服务端代码：

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.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

class AsyncServer implements Runnable {
	
	private ByteBuffer r_buff = ByteBuffer.allocate(1024);
	private ByteBuffer w_buff = ByteBuffer.allocate(1024);
	
	private static int port = 8848;

	public AsyncServer() {
		new Thread(this).start();
	}

	private void info(String str){
		System.out.println(str);
	}
	
	public void run() {
		try {
			
			
			Selector s = Selector.open();  生成一个信号监视器
			ServerSocketChannel ssc = ServerSocketChannel.open(); // 生成一个侦听端
			ssc.configureBlocking(false);// 将侦听端设为异步方式

			// 侦听端绑定到一个端口
			ssc.socket().bind(new InetSocketAddress(port));
			ssc.register(s, SelectionKey.OP_ACCEPT,new NetEventHandler());// 设置侦听端所选的异步信号OP_ACCEPT

			info("开始启动服务器");

			while (true) {
				
				int n = s.select(100);
				if (n == 0) {// 没有指定的I/O事件发生
					continue;
				}
				
				
				Set<SelectionKey> readys = s.selectedKeys();
				if(readys.size() == 0){
					continue;
				}
				
				while (readys.iterator().hasNext()) {
					
					SelectionKey key = readys.iterator().next();
					
					if (key.isAcceptable()) {// 侦听端信号触发
						info("侦听端信号触发");
						ServerSocketChannel server = (ServerSocketChannel) key.channel();
						SocketChannel sc = server.accept();
						sc.configureBlocking(false);
						sc.register(s, SelectionKey.OP_READ,new NetEventHandler());
					}
					
					if (key.isReadable()) {// 某socket可读信号
						DealwithData(key);
					}
					
					readys.iterator().remove();
				
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	

	public void DealwithData(SelectionKey key) throws IOException {
		
		NetEventHandler eventHandler = (NetEventHandler)key.attachment();
		info("eventHandler:" + eventHandler);
		
		// 由key获取指定socketchannel的引用
		SocketChannel sc = (SocketChannel) key.channel();
		r_buff.clear();
		
		int count;
		while ((count = sc.read(r_buff)) > 0);
		
		// 将r_buff内容拷入w_buff
		r_buff.flip();
		w_buff.clear();
		w_buff.put(r_buff);
		w_buff.flip();
		
		// 将数据返回给客户端
		EchoToClient(sc);

		w_buff.clear();
		r_buff.clear();
	}

	public void EchoToClient(SocketChannel sc) throws IOException {
		while (w_buff.hasRemaining())
			sc.write(w_buff);
	}

	public static void main(String args[]) {
		if (args.length > 0) {
			port = Integer.parseInt(args[0]);
		}
		new AsyncServer();
	}
}

 客户端代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;

class AsyncClient {
	private SocketChannel sc;
	private final int MAX_LENGTH = 1024;
	private ByteBuffer r_buff = ByteBuffer.allocate(MAX_LENGTH);
	private ByteBuffer w_buff = ByteBuffer.allocate(MAX_LENGTH);
	private static String host ;
	private static int port = 8848;

	public AsyncClient() {
		try {
			InetSocketAddress addr = new InetSocketAddress(host, port);
			// 生成一个socketchannel
			sc = SocketChannel.open();

			// 连接到server
			sc.connect(addr);
			while (!sc.finishConnect())
				;
			System.out.println("connection has been established!...");

			while (true) {
				// 回射消息
				String echo;
				try {
					System.err.println("Enter msg you'd like to send:  ");
					BufferedReader br = new BufferedReader(
							new InputStreamReader(System.in));
					// 输入回射消息
					echo = br.readLine();

					// 把回射消息放入w_buff中
					w_buff.clear();
					w_buff.put(echo.getBytes());
					w_buff.flip();
				} catch (IOException ioe) {
					System.err.println("sth. is wrong with br.readline() ");
				}

				// 发送消息
				while (w_buff.hasRemaining())
					sc.write(w_buff);
				w_buff.clear();

				// 进入接收状态
				Rec();
				// 间隔1秒
				Thread.currentThread().sleep(1000);
			}
		} catch (IOException ioe) {
			ioe.printStackTrace();
		} catch (InterruptedException ie) {
			ie.printStackTrace();
		}
	}

	public void Rec() throws IOException {
		int count;
		r_buff.clear();
		count = sc.read(r_buff);

		r_buff.flip();
		byte[] temp = new byte[r_buff.limit()];
		r_buff.get(temp);
		System.out.println("reply is " + count + " long, and content is: "
				+ new String(temp));
	}

	public static void main(String args[]) {
		if (args.length < 1) {// 输入需有主机名或IP地址
			try {
				System.err.println("Enter host name: ");
				BufferedReader br = new BufferedReader(new InputStreamReader(
						System.in));
				host = br.readLine();
			} catch (IOException ioe) {
				System.err.println("sth. is wrong with br.readline() ");
			}
		} else if (args.length == 1) {
			host = args[0];
		} else if (args.length > 1) {
			host = args[0];
			port = Integer.parseInt(args[1]);
		}

		new AsyncClient();
	}
}