基于Nio的echo server和echo client

最近想学netty，但平常工作中NIO用的比较少，所以最近就复习了下NIO。自己写了个基于NIO的echo例子，代码挺简单的。


echo 服务端代码

package study.nio.echo;

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;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class EchoServer implements Runnable {

	private static final Logger LOGGER = LoggerFactory.getLogger(EchoServer.class);

	private Selector selector;

	private ServerSocketChannel serverSocketChannel;

	private ByteBuffer byteBuffer = ByteBuffer.allocate(1024);

	public EchoServer(int port) {

		try {

			selector = Selector.open();
			serverSocketChannel = ServerSocketChannel.open();
			serverSocketChannel.configureBlocking(false);
			serverSocketChannel.bind(new InetSocketAddress(port));
			serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

		} catch (IOException e) {

			LOGGER.error(e.getMessage());
			System.exit(0);
		}
	}

	@Override
	public void run() {

		if (selector.isOpen() == false) {

			LOGGER.warn("echo server selector is not start");
			return;
		}
		LOGGER.warn("echo server started");
		while (true) {

			try {

				selector.select();
				Set<SelectionKey> selectedKeys = selector.selectedKeys();
				Iterator<SelectionKey> keysIter = selectedKeys.iterator();
				while (keysIter.hasNext()) {

					SelectionKey key = keysIter.next();
					keysIter.remove();

					if (key.isAcceptable()) {

						ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
						SocketChannel sc = ssc.accept();
						sc.configureBlocking(false);
						LOGGER.info("echo server is connected");
						sc.register(selector, SelectionKey.OP_READ);
					} else if (key.isReadable()) {

						SocketChannel sc = (SocketChannel) key.channel();
						StringBuilder strb = new StringBuilder(1024);
						while (sc.read(byteBuffer) > 0) {

							byteBuffer.flip();
							byte[] bytes = new byte[byteBuffer.remaining()];
							byteBuffer.get(bytes);
							byteBuffer.clear();
							String msg = new String(bytes);
							LOGGER.info("echo server read msg:" + msg);
							strb.append(msg);
						}
						ByteBuffer writeBuffer = ByteBuffer.wrap(strb.toString().getBytes());
						LOGGER.info("{}", writeBuffer.position());
						LOGGER.info("{}", writeBuffer.limit());
						sc.write(writeBuffer);
					}
				}

			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}

	}

}

echo 客户端代码

package study.nio.echo;

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.util.Iterator;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class EchoClient implements Runnable {

	private static final Logger LOGGER = LoggerFactory.getLogger(EchoClient.class);

	private Selector selector;

	private SocketChannel socketChannel;

	private ByteBuffer byteBuffer;

	public EchoClient(String ip, int port) {

		try {
			selector = Selector.open();
			socketChannel = SocketChannel.open();
			socketChannel.configureBlocking(false);
			socketChannel.connect(new InetSocketAddress(ip, port));
			socketChannel.register(selector, SelectionKey.OP_CONNECT);
		} catch (IOException e) {

			LOGGER.error(e.getMessage());
			System.exit(0);
		}
	}

	@Override
	public void run() {

		if (selector.isOpen() == false) {
			
			LOGGER.warn("echo client selector is not start");
			return;
		}
		LOGGER.warn("echo client started");
		while (true) {

			try {
				if (selector.isOpen() == false) {
					 LOGGER.warn("selector is closed");
					 break;
				}
				selector.select();
				Iterator<SelectionKey> ite = this.selector.selectedKeys().iterator();
				while (ite.hasNext()) {

					SelectionKey key = (SelectionKey) ite.next();
					ite.remove();
					if (key.isConnectable()) {

						SocketChannel channel = (SocketChannel) key.channel();
						// 如果正在连接，则完成连接
						if (channel.isConnectionPending()) {
							channel.finishConnect();
						}
						LOGGER.info("echo client is connected");
						// 设置成非阻塞
						channel.configureBlocking(false);
						channel.write(ByteBuffer.wrap("this echo client msg,over".getBytes()));
						channel.register(selector, SelectionKey.OP_READ);
					} else if (key.isReadable()) {
						
						SocketChannel sc = (SocketChannel) key.channel();
						StringBuilder strb = new StringBuilder(1024);
						while (sc.read(byteBuffer) > 0) {

							byteBuffer.flip();
							byte[] bytes = new byte[byteBuffer.remaining()];
							byteBuffer.get(bytes);
							byteBuffer.clear();
							String msg = new String(bytes);
							strb.append(msg);
						}
						LOGGER.info("echo client read msg:" + strb.toString());
						break;
					}
				}

			} catch (IOException e) {
				
				LOGGER.error(e.getMessage());
				System.exit(0);
			}

		}
	}

}

启动测试的代码

package study.nio.echo;

public class EchoTest1 {

	public static void main(String[] args) {
		
		EchoClient echoClient = new EchoClient("127.0.0.1", EchoTest.serverPort);
		echoClient.run();
	}
}

package study.nio.echo;

public class EchoTest1 {

	public static void main(String[] args) {
		
		EchoClient echoClient = new EchoClient("127.0.0.1", EchoTest.serverPort);
		echoClient.run();
	}
}