Java NIOの簡単な例

サーバ側:

package nioT;

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.nio.charset.Charset;
import java.util.Iterator;

public class NIOServer1 {
	//      
	private static final String LocalCharSetName = "UTF-8";

	//           
	private static final int Listenning_Port = 8888;

	//      
	private static final int Buffer_Size = 1024;

	//     ,    
	private static final int TimeOut = 3000;

	public static void main(String[] args) throws IOException {
		//                 Socket  .         
		ServerSocketChannel serverChannel = ServerSocketChannel.open();

		serverChannel.socket().bind(new InetSocketAddress(Listenning_Port));
		serverChannel.configureBlocking(false);

		//          serverChannel      
		Selector selector = Selector.open();
		serverChannel.register(selector, SelectionKey.OP_ACCEPT);

		while (true) {
			//         
			if (selector.select(TimeOut) == 0) {
				System.out.println(".");
				continue;
			}

			//            
			Iterator keyIter = selector.selectedKeys().iterator();

			//              
			while (keyIter.hasNext()) {
				SelectionKey key = keyIter.next();
				//              ,    clientChannel    
				if (key.isAcceptable()) {
					SocketChannel clientChannel = ((ServerSocketChannel) key.channel()).accept();
					clientChannel.configureBlocking(false);
					clientChannel.register(selector, SelectionKey.OP_READ,
							ByteBuffer.allocate(Buffer_Size));
				}

				//        
				if (key.isReadable()) {
					//            
					SocketChannel clientChannel = (SocketChannel) key.channel();

					//               
					ByteBuffer buffer = (ByteBuffer) key.attachment();
					buffer.clear();

					//             
					long bytesRead = clientChannel.read(buffer);

					if (bytesRead == -1) {
						//           
						clientChannel.close();
					} else {
						//              
						buffer.flip();
						//         (  Charset    )
						String receivedString = Charset
								.forName(LocalCharSetName).newDecoder().decode(buffer).toString();

						//        
						System.out.println("     :" + receivedString);

						//        
						String sendString = "  ,   .         " + receivedString;

						//           (  Charset    )      
						buffer = ByteBuffer.wrap(sendString.getBytes(LocalCharSetName));

						//     
						clientChannel.write(buffer);

						//                
						key.interestOps(SelectionKey.OP_READ | SelectionKey.OP_WRITE);
					}
				}

				keyIter.remove();
			}
		}

	}
}

クライアント:

package nioT;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;

public class NIOClient1Test {

	public static void main(String[] args) throws UnknownHostException,
			IOException {
		Socket s = new Socket("localhost", 8888);

		InputStream inStream = s.getInputStream();
		OutputStream outStream = s.getOutputStream();

		//   
		PrintWriter out = new PrintWriter(outStream, true);
		out.println("getPublicKey  ！");
		out.flush();

		s.shutdownOutput();//     

		//   
		Scanner in = new Scanner(inStream);

		StringBuilder sb = new StringBuilder();
		while (in.hasNextLine()) {
			String line = in.nextLine();
			sb.append(line);
		}

		String response = sb.toString();
		System.out.println("response=" + response);

	}
}

実行結果
サービス:

.
     :getPublicKey  ！

.

クライアント:

response=  ,   .         getPublicKey  ！