socket服务类

package test.sockettest;
/**
 * 
 * @author chenjd
 */
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

public class NBServer {
	int port = 8090;
	int BUFFERSIZE = 1024;
	Selector selector = null;
	ServerSocketChannel serverChannel = null;
	HashMap clientChannelMap = null;// 用来存放每一个客户连接对应的套接字和通道

	public NBServer(int port) {
		this.clientChannelMap = new HashMap();
		this.port = port;
	}

	public void initialize() throws IOException {
		// 初始化，分别实例化一个选择器，一个服务器端可选择通道
		this.selector = Selector.open();
		this.serverChannel = ServerSocketChannel.open();
		this.serverChannel.configureBlocking(false);
		InetAddress localhost = InetAddress.getLocalHost();
		InetSocketAddress isa = new InetSocketAddress(localhost, this.port);
		this.serverChannel.socket().bind(isa);// 将该套接字绑定到服务器某一可用端口
	}

	// 结束时释放资源
	public void finalize() throws IOException {
		this.serverChannel.close();
		this.selector.close();
	}

	// 将读入字节缓冲的信息解码
	public String decode(ByteBuffer byteBuffer) throws CharacterCodingException {
		Charset charset = Charset.forName("ISO-8859-1");
		CharsetDecoder decoder = charset.newDecoder();
		CharBuffer charBuffer = decoder.decode(byteBuffer);
		String result = charBuffer.toString();
		return result;
	}

	// 监听端口，当通道准备好时进行相应操作
	public void portListening(String data) throws IOException, InterruptedException {
		// 服务器端通道注册OP_ACCEPT事件
		SelectionKey acceptKey = this.serverChannel.register(this.selector,
				SelectionKey.OP_ACCEPT);
		// 当有已注册的事件发生时,select()返回值将大于0
		while (acceptKey.selector().select() > 0) {
			System.out.println("event happened");
			// 取得所有已经准备好的所有选择键
			Set readyKeys = this.selector.selectedKeys();
			// 使用迭代器对选择键进行轮询
			Iterator i = readyKeys.iterator();
			while (i.hasNext()) {
				SelectionKey key = (SelectionKey) i.next();
				i.remove();// 删除当前将要处理的选择键
				if (key.isAcceptable()) {// 如果是有客户端连接请求
					System.out.println("more client connect in!");
					ServerSocketChannel nextReady = (ServerSocketChannel) key
							.channel();
					// 获取客户端套接字
					Socket s = nextReady.accept().socket();
					// 设置对应的通道为异步方式并注册感兴趣事件
					s.getChannel().configureBlocking(false);
					SelectionKey readWriteKey = s.getChannel().register(
							this.selector,
							SelectionKey.OP_READ | SelectionKey.OP_WRITE);
					// 将注册的事件与该套接字联系起来
					readWriteKey.attach(s);
					// 将当前建立连接的客户端套接字及对应的通道存放在哈希表//clientChannelMap中
					this.clientChannelMap.put(s, new ClientChInstance(s
							.getChannel()));
				} else if (key.isReadable()) {// 如果是通道读准备好事件
					System.out.println("Readable");
					// 取得选择键对应的通道和套接字
					SelectableChannel nextReady = (SelectableChannel) key
							.channel();
					Socket socket = (Socket) key.attachment();
					// 处理该事件，处理方法已封装在类ClientChInstance中
					this.readFromChannel(socket.getChannel(),
							(ClientChInstance) this.clientChannelMap
									.get(socket));
				} else if (key.isWritable()) {// 如果是通道写准备好事件
					System.out.println("writeable");
					// 取得套接字后处理，方法同上
					Socket socket = (Socket) key.attachment();
					SocketChannel channel = (SocketChannel) socket.getChannel();
//					this.writeToChannel(channel, "This is from server!");
					this.writeToChannel(channel, data);
				}
			}
		}
	}

	// 对通道的写操作
	public void writeToChannel(SocketChannel channel, String message)
			throws IOException {
		ByteBuffer buf = ByteBuffer.wrap(message.getBytes());
		int nbytes = channel.write(buf);
	}

	// 对通道的读操作
	public void readFromChannel(SocketChannel channel,
			ClientChInstance clientInstance) throws IOException,
			InterruptedException {
		ByteBuffer byteBuffer = null;
		try{
			byteBuffer = ByteBuffer.allocate(BUFFERSIZE);
			int nbytes = channel.read(byteBuffer);
		}catch(Exception e){
			clientChannelMap.remove(channel.socket());
			channel.close();
			e=null;
			return;
		}
		byteBuffer.flip();
		String result = this.decode(byteBuffer);
		// 当客户端发出”@exit”退出命令时，关闭其通道
		if (result.indexOf("@exit") >= 0||result.indexOf("q")>=0) {
			channel.close();
		}
//		else if(result.indexOf("@close") >= 0){//关闭服务
//			channel.close();
//			this.finalize();
//		}
		else {
			clientInstance.append(result.toString());
			// 读入一行完毕，执行相应操作
			if (result.indexOf("\n") >= 0) {
				System.out.println("client input" + result);
				clientInstance.execute();
			}
		}
	}

	// 该类封装了怎样对客户端的通道进行操作，具体实现可以通过重载execute()方法
	public class ClientChInstance {
		SocketChannel channel;
		StringBuffer buffer = new StringBuffer();

		public ClientChInstance(SocketChannel channel) {
			this.channel = channel;
		}

		public void execute() throws IOException {
			String message = "This is response after reading from channel!";
			writeToChannel(this.channel, message);
			buffer = new StringBuffer();
		}

		// 当一行没有结束时，将当前字窜置于缓冲尾
		public void append(String values) {
			buffer.append(values);
		}
	}

	// 主程序
	public static void main(String[] args) {
		NBServer nbServer = new NBServer(8090);
		try {
			nbServer.initialize();
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(-1);
		}
		try {
			nbServer.portListening("This is from server!");
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}