最近寫了個Java NIO聊天室聊天的程序，NIO學習起來比較困難的，我的代碼能給大家起到一個拋磚引玉的作用！

服務端：

package test.javanio;  
 
/**  
 * @author   
 * @version   
 * CreateTime：2010-12-1 下午05:12:11  
 * Description：  
 */ 
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.Date;  
import java.util.Iterator;  
import java.util.logging.Level;  
import java.util.logging.Logger;  
 
public class MySocketServer implements Runnable {  
 
    private boolean running;  
 
    private Selector selector;  
    String writeMsg;  
    StringBuffer sb = new StringBuffer();  
    SelectionKey ssckey;  
 
    public MySocketServer() {  
 
        running = true;  
 
    }  
 
    public void init() {  
        try {  
            selector = Selector.open();  
            ServerSocketChannel ssc = ServerSocketChannel.open();  
            ssc.configureBlocking(false);  
            ssc.socket().bind(new InetSocketAddress(2345));  
            ssckey = ssc.register(selector, SelectionKey.OP_ACCEPT);  
            System.out.println("server is starting..." + new Date());  
        } catch (IOException ex) {  
            Logger.getLogger(MySocketServer.class.getName()).log(Level.SEVERE,  
                    null, ex);  
        }  
    }  
 
    public static void main(String[] args) {  
        MySocketServer server = new MySocketServer();  
        new Thread(server).start();  
 
    }  
 
    public void execute() {  
        try {  
            while (running) {  
                int num = selector.select();  
                if (num > 0) {  
                    Iterator<SelectionKey> it = selector.selectedKeys()  
                            .iterator();  
                    while (it.hasNext()) {  
                        SelectionKey key = it.next();  
                        it.remove();  
                        if (!key.isValid())  
                            continue;  
                        if (key.isAcceptable()) {  
                            System.out.println("isAcceptable");  
                            getConn(key);  
                        } else if (key.isReadable()) {  
                            System.out.println("isReadable");  
                            readMsg(key);  
                        }  
 
                        else if (key.isValid() && key.isWritable()) {  
                            if (writeMsg != null) {  
                                System.out.println("isWritable");  
                                writeMsg(key);  
                            }  
 
                        }  
 
                        else 
                            break;  
 
                    }  
 
                }  
                Thread.yield();  
            }  
 
        } catch (IOException ex) {  
            Logger.getLogger(MySocketServer.class.getName()).log(Level.SEVERE,  
                    null, ex);  
        }  
    }  
 
    private void getConn(SelectionKey key) throws IOException {  
        ServerSocketChannel ssc = (ServerSocketChannel) key.channel();  
        SocketChannel sc = ssc.accept();  
        sc.configureBlocking(false);  
        sc.register(selector, SelectionKey.OP_READ);  
        System.out.println("build connection :" 
                + sc.socket().getRemoteSocketAddress());  
    }  
 
    private void readMsg(SelectionKey key) throws IOException {  
        sb.delete(0, sb.length());  
        SocketChannel sc = (SocketChannel) key.channel();  
        System.out.print(sc.socket().getRemoteSocketAddress() + " ");  
        ByteBuffer buffer = ByteBuffer.allocate(1024);  
        buffer.clear();  
        int len = 0;  
        StringBuffer sb = new StringBuffer();  
        while ((len = sc.read(buffer)) > 0) {  
            buffer.flip();  
            sb.append(new String(buffer.array(), 0, len));  
        }  
        if (sb.length() > 0)  
            System.out.println("get from client:" + sb.toString());  
        if (sb.toString().trim().toLowerCase().equals("quit")) {  
            sc.write(ByteBuffer.wrap("BYE".getBytes()));  
            System.out.println("client is closed " 
                    + sc.socket().getRemoteSocketAddress());  
            key.cancel();  
            sc.close();  
            sc.socket().close();  
 
        } else {  
            String toMsg = sc.socket().getRemoteSocketAddress() + "said:" 
                    + sb.toString();  
            System.out.println(toMsg);  
 
            writeMsg = toMsg;  
 
            /*  
             * Iterator<SelectionKey> it=key.selector().keys().iterator();  
             *   
             * while(it.hasNext()){ SelectionKey skey=it.next();  
             * if(skey!=key&&skey!=ssckey){ SocketChannel client=(SocketChannel)  
             * skey.channel(); client.write(ByteBuffer.wrap(toMsg.getBytes()));  
             * }  
             *   
             * }  
             */ 
 
            /*  
             *   
             * key.attach(toMsg);  
             * key.interestOps(key.interestOps()|SelectionKey.OP_WRITE);  
             */ 
            Iterator<SelectionKey> it = key.selector().keys().iterator();  
 
            while (it.hasNext()) {  
                SelectionKey skey = it.next();  
                if (skey != key && skey != ssckey) {  
                    if (skey.attachment() != null) {  
                        String str = (String) skey.attachment();  
                        skey.attach(str + toMsg);  
                    } else {  
                        skey.attach(toMsg);  
                    }  
                    skey  
                            .interestOps(skey.interestOps()  
                                    | SelectionKey.OP_WRITE);  
                }  
 
            }  
            selector.wakeup();// 可有可無  
 
        }  
 
    }  
 
    public void run() {  
        init();  
        execute();  
    }  
 
    private void writeMsg(SelectionKey key) throws IOException {  
 
        System.out.println("++++enter write+++");  
        SocketChannel sc = (SocketChannel) key.channel();  
        String str = (String) key.attachment();  
 
        sc.write(ByteBuffer.wrap(str.getBytes()));  
        key.interestOps(SelectionKey.OP_READ);  
    }  
} 

客戶端：

package test.javanio;  
 
/**  
 * @author   
 * @version   
 * CreateTime：2010-12-1 下午05:12:46  
 * Description：  
 */ 
import java.io.BufferedReader;  
import java.io.IOException;  
import java.io.InputStreamReader;  
import java.net.InetSocketAddress;  
import java.nio.ByteBuffer;  
import java.nio.channels.Selector;  
import java.nio.channels.SocketChannel;  
import java.util.logging.Level;  
import java.util.logging.Logger;  
import java.util.Currency.*;  
 
public class MySocketClient implements Runnable {  
    Selector selector;  
 
    boolean running;  
 
    SocketChannel sc;  
 
    public MySocketClient() {  
        running = true;  
 
    }  
 
    public void init() {  
        try {  
            sc = SocketChannel.open();  
            sc.configureBlocking(false);  
            sc.connect(new InetSocketAddress("localhost", 2345));  
 
        } catch (IOException ex) {  
            Logger.getLogger(MySocketClient.class.getName()).log(Level.SEVERE,  
                    null, ex);  
        }  
    }  
 
    public static void main(String[] args) {  
 
        MySocketClient client = new MySocketClient();  
        new Thread(client).start();  
    }  
 
    public void execute() {  
 
        int num = 0;  
        try {  
            while (!sc.finishConnect()) {  
            }  
        } catch (IOException ex) {  
            Logger.getLogger(MySocketClient.class.getName()).log(Level.SEVERE,  
                    null, ex);  
        }  
 
        ReadKeyBoard rkb = new ReadKeyBoard();  
        new Thread(rkb).start();  
        while (running) {  
            try {  
 
                ByteBuffer buffer = ByteBuffer.allocate(1024);  
                buffer.clear();  
 
                StringBuffer sb = new StringBuffer();  
                Thread.sleep(500);  
 
                while ((num = sc.read(buffer)) > 0) {  
                    sb.append(new String(buffer.array(), 0, num));  
                    buffer.clear();  
                }  
                if (sb.length() > 0)  
                    System.out.println(sb.toString());  
                if (sb.toString().toLowerCase().trim().equals("bye")) {  
                    System.out.println("closed....");  
 
                    sc.close();  
                    sc.socket().close();  
                    rkb.close();  
                    running = false;  
                }  
            } catch (InterruptedException ex) {  
                Logger.getLogger(MySocketClient.class.getName()).log(  
                        Level.SEVERE, null, ex);  
            } catch (IOException ex) {  
                Logger.getLogger(MySocketClient.class.getName()).log(  
                        Level.SEVERE, null, ex);  
            }  
        }  
 
    }  
 
    public void run() {  
        init();  
        execute();  
    }  
 
    class ReadKeyBoard implements Runnable {  
 
        boolean running2 = true;  
 
        public ReadKeyBoard() {  
 
        }  
 
        public void close() {  
            running2 = false;  
        }  
 
        public void run() {  
            BufferedReader reader = new BufferedReader(new InputStreamReader(  
                    System.in));  
            while (running2) {  
                try {  
                    System.out.println("enter some commands:");  
                    String str = reader.readLine();  
                    sc.write(ByteBuffer.wrap(str.getBytes()));  
 
                } catch (IOException ex) {  
                    Logger.getLogger(ReadKeyBoard.class.getName()).log(  
                            Level.SEVERE, null, ex);  
                }  
            }  
 
        }  
 
    }  
} 

原文鏈接：http://gcguchao8888-sina-com.iteye.com/blog/839021

【編輯推薦】

1. 多線程NIO客戶端實例
2. 用nio實現Echo服務
3. Java NIO 深入研究
4. Java NIO聊天窗口實例
5. Java NIO 經典實例代碼