nio demo

package com.nio.client;import java.io.IOException;import java.net.InetSocketAddress;import java.net.ServerSocket;import java.net.Socket;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.text.SimpleDateFormat;import java.util.Date;import java.util.Iterator;import java.util.Set;public class NIOServer {    /* 缓冲区大小 */    private static final int BLOCK_SIZE = 4096;    /* 接收数据缓冲区大小 */    private ByteBuffer recieveBuffer = ByteBuffer.allocate(BLOCK_SIZE);    /* 发送数据缓冲区大小 */    private ByteBuffer sendBuffer = ByteBuffer.allocate(BLOCK_SIZE);    /*持有一个Selector*/    private Selector selector;    public NIOServer(){    }    public NIOServer(int port) throws IOException{        /*SocketServerChannel：可以监听新进来的TCP连接的通道, 就像标准IO中的ServerSocket一样*/        /*创建服务器套接字通道：SocketServerChannel，内部就是实例化了一个SocketServerChannelImpl*/        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();        /* 服务器配置为非阻塞 */        serverSocketChannel.configureBlocking(Boolean.FALSE);        /* 获取一个socket */        ServerSocket serverSocket = serverSocketChannel.socket();        /* 通过socket 绑定地址 */        serverSocket.bind(new InetSocketAddress("localhost",port));        /* 获取Selector:实际上window是创建了WindowsSelectorImpl实例 */        selector = Selector.open();        /* 注册到accept事件到 selector，等待连接 */        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);        System.out.println("NIO Server Start.........................");    }    /**一直不断的监听*/    public void listen() throws IOException {        while (true){            // 监控注册在Selector上的ServerSocketChannel，返回值代表有多少channel已经就绪，可以进行I/O操作了            int ready = selector.select();            if (ready > 0) {               /*                * selectedKeys()返回一个SelectionKey的集合，因为完全有可能在这个Selector注册多个SelectionKey                * 比如OP_ACCEPT,OP_READ,OP_WRITE等                * 其中每个SelectionKey代表了一个可以进行IO操作的channel                * 一个ServerSocketChannel可以进行IO操作意味着有新的TCP连接连入了                */                Set<SelectionKey> keys =  selector.selectedKeys();                SelectionKey key = null;                for(Iterator<SelectionKey> it = keys.iterator();it.hasNext();){                    key = (SelectionKey)it.next();                    // 需要将处理过的key从selectedKeys这个集合中删除                    it.remove();                    handleKey(key);                }            }        }    }    /**处理请求*/    public void handleKey(SelectionKey key) throws IOException{        if (key == null) {            System.out.println("SelectionKey is null");            return;        }        ServerSocketChannel serverSocketChannel = null;        SocketChannel socketChannel = null;        Socket socket = null;        int count = 0;        /* 判断这个SelectionKey对应的channel是否已准备好接收新的TCP连接 */        if (key.isAcceptable()) {            /* 从SelectionKey得到对应的channel */            serverSocketChannel = (ServerSocketChannel)key.channel();            /* 接受新的TCP连接(来自客户端) */            socketChannel = serverSocketChannel.accept();            /* 配置为非阻塞  */            socketChannel.configureBlocking(Boolean.FALSE);            /* 注册到selector，等待读取 */            socketChannel.register(selector,SelectionKey.OP_READ);        } else if (key.isReadable()) { //判断该通道是否已准备好读            /* 返回为之创建此键的通道 */            socketChannel = (SocketChannel)key.channel();            /* 将接收数据的缓冲区清空以备下次读取 */            recieveBuffer.clear();            /* 读取服务器发送的数据到recieveBuffer */            count = socketChannel.read(recieveBuffer);            if (count >0) {                String recvText = new String(recieveBuffer.array(),0,count);                System.out.println("服务器端接受客户端数据--: " + recvText);                socketChannel.register(selector, SelectionKey.OP_WRITE);            }        } else if (key.isWritable()) {//判断该通道是否已准备好写            socketChannel = (SocketChannel)key.channel();            /* 将缓冲区清空以备下次写入 */            sendBuffer.clear();            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");            String data = dateFormat.format(new Date());            /* 向缓冲区中输入数据 */            sendBuffer.put(data.getBytes(Charset.defaultCharset()));            /* 将数据输出到通道*/            socketChannel.write(sendBuffer);            System.out.println("服务器端向客户端发送数据--: " + data);            /* 又注册到selector，等待读取 */            socketChannel.register(selector, SelectionKey.OP_READ);        }    }    public static void main(String[] args) throws IOException {        int port = 22222;        NIOServer server = new NIOServer(port);        server.listen();    }
}
package com.nio.client;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.nio.charset.Charset;import java.util.Iterator;import java.util.Set;public class NIOClient {    /* 缓冲区大小 */    private static final int BLOCK_SIZE = 4096;    /* 接收数据缓冲区大小 */    private ByteBuffer recieveBuffer = ByteBuffer.allocate(BLOCK_SIZE);    /* 发送数据缓冲区大小 */    private ByteBuffer sendBuffer = ByteBuffer.allocate(BLOCK_SIZE);    /* 服务器端地址 */    private final static InetSocketAddress SERVER_ADDRESS =        new InetSocketAddress("localhost", 22222);    public void handle() throws IOException{        /* 创建一个SocketChannel */        SocketChannel socketChannel = SocketChannel.open();        /* 设为非阻塞模式 */        socketChannel.configureBlocking(Boolean.FALSE);        /* 创建Selector */        Selector selector = Selector.open();        /* 注册连接服务端socket动作 */        socketChannel.register(selector, SelectionKey.OP_CONNECT);        /* 连接到服务器 */        socketChannel.connect(SERVER_ADDRESS);        Set<SelectionKey> keys = null;        Iterator<SelectionKey> it = null;        SelectionKey key = null;        int count = 0;        String recvText = null;        while (true) {            /* 监控注册在Selector上的SocketChannel，返回值代表有多少channel已经就绪，可以进行I/O操作了*/            int ready = selector.select();               /* 其中每个SelectionKey代表了一个可以进行IO操作的channel */            keys = selector.selectedKeys();            it = keys.iterator();            while (it.hasNext()) {                key = (SelectionKey)it.next();                // 判断该通道是否可以进行连接操作                if (key.isConnectable()) {                    System.out.println("客户端开始连接......");                        /* 返回为之创建此键的通道 */                    socketChannel = (SocketChannel)key.channel();                    if (socketChannel.isConnectionPending()) {                        socketChannel.finishConnect();                        System.out.println("完成连接!");                        sendBuffer.clear();                        sendBuffer.put("我可以连接吗".getBytes(Charset.defaultCharset()));                        sendBuffer.flip();                        socketChannel.write(sendBuffer);                    }                        /* 又注册到selector，等待读取 */                    socketChannel.register(selector, SelectionKey.OP_READ);                } else if (key.isReadable()) { //判断该通道是否可以读                        /* 返回为之创建此键的通道 */                    socketChannel = (SocketChannel)key.channel();                    //将接收数据缓冲区清空以备下次读取                    recieveBuffer.clear();                    //读取服务器发送来的数据到缓冲区中                    count = socketChannel.read(recieveBuffer);                    if (count > 0) {                        recvText = new String(recieveBuffer.array(),0,count,Charset.defaultCharset());                        System.out.println("客户端接受服务器端数据=> "+recvText);                            /* 又注册到selector，等待写入 */                        socketChannel.register(selector, SelectionKey.OP_WRITE);                    }                } else if (key.isWritable()) { //判断该通道是否可以写                        /* 返回为之创建此键的通道 */                    socketChannel = (SocketChannel)key.channel();                    //将发送数据缓冲区清空以备下次读取                    sendBuffer.clear();                    String data = String.valueOf(Math.round(Math.random() * 100 + 1));                    sendBuffer.put(data.getBytes(Charset.defaultCharset()));                    //将缓冲区各标志复位,因为向里面put了数据标志被改变要想从中读取数据发向服务器,就要复位                    sendBuffer.flip();                    socketChannel.write(sendBuffer);                    System.out.println("客户端向服务器端发送数据=> " + data);                    socketChannel.register(selector, SelectionKey.OP_READ);                }            }            keys.clear();        }    }    public static void main(String[] args) throws IOException {        NIOClient client = new NIOClient();        client.handle();    }}