最简单易懂的tcp nio非阻塞流 示例

最简单易懂的tcp nio非阻塞流 示例

NIO TCP 通信通过  ServerSocketChannel ,SocketChannel，Selector 来完成
 

1.服务器端
 

package com.nio.tcp;

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;

public class TCPNIOServer {
	public static void main(String[] args) throws IOException {
		System.out.println("服务端已经启动，在 8080 端口监听 ......");
		ServerSocketChannel channel = ServerSocketChannel.open();// 打开服务通道
		channel.configureBlocking(false);// 设置为非阻塞
		channel.socket().bind(new InetSocketAddress(8080));// 绑定连接 和 监听端口
		
		startListen(channel);
		
		channel.close();
	}

	private static void startListen(ServerSocketChannel channel)  throws IOException {
		Selector selector = Selector.open();// 打开选择器
		channel.register(selector, SelectionKey.OP_ACCEPT);// 通道注册到选择器，监听接受事件
		// 轮训 获取选择 已经准备就绪 的事件
		while (selector.select() > 0) {
			Iterator iterator = selector.selectedKeys().iterator();// 获取当前选择器所有注册的已经就绪的监听事件
			while (iterator.hasNext()) {
				SelectionKey selectionKey = iterator.next();
				if (selectionKey.isAcceptable()) {

					doAcceptable(channel, selector);

				} else if (selectionKey.isReadable()) {

					doReadable(channel, selector, selectionKey);

				} else if (selectionKey.isConnectable()) {

				} else if (selectionKey.isWritable()) {

				}
                iterator.remove();
			}

		}
		
	}

	private static void doAcceptable(ServerSocketChannel channel, Selector selector) throws IOException {
		SocketChannel socketChannel = channel.accept();// 接受就绪,获取客户端连接
		if(socketChannel==null)
		{
			return;
		}
		socketChannel.configureBlocking(false);// 设置非阻塞
		socketChannel.register(selector, SelectionKey.OP_READ);// 将通道注册到服务器上，监听读事件
	}

	private static void doReadable(ServerSocketChannel channel, Selector selector, SelectionKey selectionKey) throws IOException {
		SocketChannel socketChannel = (SocketChannel) selectionKey.channel();// 获取当前选择器状态的通道
		// 分配缓冲区，读取数据
		ByteBuffer buffer = ByteBuffer.allocate(1024);
		int len = 0;
		while ((len = socketChannel.read(buffer)) > 0) {
			buffer.flip();
			System.out.println(new String(buffer.array(), 0, len));
			buffer.clear();
		}

	}

}

2.客户端
 

package com.nio.tcp;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import java.util.Date;
import java.util.Scanner;

public class TCPNIOClient {
	public static void main(String[] args) {
		System.out.println("客户端已经启动...");
		
		SocketChannel socketChannel=null;
		try {
			socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 8080));//创建通道
			socketChannel.configureBlocking(false);// 设置非阻塞
			
			ByteBuffer buffer = ByteBuffer.allocate(1024);
	
			String data="忍耐和坚持虽是痛苦的事情，但却能渐渐地为你带来好处。";
			buffer.put(data.getBytes());
			buffer.flip();
			socketChannel.write(buffer);
			buffer.clear();
		} catch (IOException e) {
			e.printStackTrace();
		}
		finally
		{
			try {
				socketChannel.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
}

测试运行结果：

首先启动 服务器端 TCPNIOServer
服务端已经启动，在 8080 端口监听 ......

忍耐和坚持虽是痛苦的事情，但却能渐渐地为你带来好处。

然后启动 客户端 TCPNIOClient

客户端已经启动...


图解：