TCP/IP 无阻塞 Socket

package com.io;

import java.net.InetSocketAddress;
import java.net.ServerSocket;
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.nio.charset.Charset;

public class NewSocketServer {
	public static void main(String[] args) throws Exception {
		int port = 9527;
		//打开选择器
		Selector selector = Selector.open();
		//打开服务器套接字通道
		ServerSocketChannel ssc = ServerSocketChannel.open();
		//检索与此通道关联的服务器套接字。
		ServerSocket serverSocket = ssc.socket();
		//将 ServerSocket 绑定到特定地址（IP 地址和端口号）
		serverSocket.bind(new InetSocketAddress(port));
		System.out.println("Server listen on port: " + port);
		//调整此通道的阻塞模式。
		ssc.configureBlocking(false);
		//向给定的选择器注册此通道，返回一个选择键。SelectionKey.OP_ACCEPT--用于套接字接受操作的操作集位
		ssc.register(selector, SelectionKey.OP_ACCEPT);
		while (true) {
			//timeout - 如果为正，则在等待某个通道准备就绪时最多阻塞 timeout 毫秒；如果为零，则无限期地阻塞；必须为非负数 
			int nKeys = selector.select(1000);
			if (nKeys > 0) {
				for (SelectionKey key : selector.selectedKeys()) {
					//测试此键的通道是否已准备好接受新的套接字连接--如果此键的通道不支持套接字接受操作，则此方法始终返回 false。
					if (key.isAcceptable()) {
						ServerSocketChannel server = (ServerSocketChannel) key
								.channel();
						SocketChannel sc = server.accept();
						if (sc == null) {
							continue;
						}
						sc.configureBlocking(false);
						sc.register(selector, SelectionKey.OP_READ);
					} else if (key.isReadable()) {
						//分配一个新的字节缓冲区。
						ByteBuffer buffer = ByteBuffer.allocate(1024);
						SocketChannel sc = (SocketChannel) key.channel();
						int readBytes = 0;
						String message = null;
						try {
							int ret;
							try {
								while ((ret = sc.read(buffer)) > 0) {
									readBytes += ret;
								}
							} catch (Exception e) {
								readBytes = 0;
								// IGNORE
							} finally {
								//反转此缓冲区。首先对当前位置设置限制，然后将该位置设置为零
								buffer.flip();
							}
							if (readBytes > 0) {
								message = Charset.forName("UTF-8").decode(
										buffer).toString();
								buffer = null;
							}
						} finally {
							if (buffer != null) {
								buffer.clear();
							}
						}
						if (readBytes > 0) {
							System.out.println("Message from client: "
									+ message);
							if ("quit".equalsIgnoreCase(message.trim())) {
								sc.close();
								selector.close();
								System.out.println("Server has been shutdown!");
								System.exit(0);
							}
							String outMessage = "Server response：" + message;
							sc.write(Charset.forName("UTF-8")
									.encode(outMessage));
						}
					}
				}
				selector.selectedKeys().clear();
			}
		}
	}

}

package com.io;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;

public class NewSokectClient {
	public static void main(String[] args) throws Exception {
		int port = 9527;
		SocketChannel channel = SocketChannel.open();
		channel.configureBlocking(false);
		SocketAddress target = new InetSocketAddress("127.0.0.1", port);
		channel.connect(target);
		Selector selector = Selector.open();
		//用于套接字连接操作的操作集位。
		channel.register(selector, SelectionKey.OP_CONNECT);
		BufferedReader systemIn = new BufferedReader(new InputStreamReader(
				System.in));
		while (true) {
			if (channel.isConnected()) {
				String command = systemIn.readLine();
				channel.write(Charset.forName("UTF-8").encode(command));
				if (command == null || "quit".equalsIgnoreCase(command.trim())) {
					systemIn.close();
					channel.close();
					selector.close();
					System.out.println("Client quit!");
					System.exit(0);
				}
			}
			int nKeys = selector.select(1000);
			if (nKeys > 0) {
				for (SelectionKey key : selector.selectedKeys()) {
					if (key.isConnectable()) {
						SocketChannel sc = (SocketChannel) key.channel();
						sc.configureBlocking(false);
						sc.register(selector, SelectionKey.OP_READ);
						sc.finishConnect();
					} else if (key.isReadable()) {
						ByteBuffer buffer = ByteBuffer.allocate(1024);
						SocketChannel sc = (SocketChannel) key.channel();
						int readBytes = 0;
						try {
							int ret = 0;
							try {
								while ((ret = sc.read(buffer)) > 0) {
									readBytes += ret;
								}
							} finally {
								buffer.flip();
							}
							if (readBytes > 0) {
								System.out.println(Charset.forName("UTF-8")
										.decode(buffer).toString());
								buffer = null;
							}
						} finally {
							if (buffer != null) {
								buffer.clear();
							}
						}
					}
				}
				selector.selectedKeys().clear();
			}
		}

	}
}