最近一直在忙著JAVA NIO的知識，花了一下午的時(shí)間，總算寫出了一個(gè)可以運(yùn)行的程序，廢話少說，上代碼！

Java代碼：

import java.io.IOException;  
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.util.Iterator;  
import java.util.Set;  
 
public class NIOServer {  
      
    /*標(biāo)識數(shù)字*/ 
    private  int flag = 0;  
    /*緩沖區(qū)大小*/ 
    private  int BLOCK = 4096;  
    /*接受數(shù)據(jù)緩沖區(qū)*/ 
    private  ByteBuffer sendbuffer = ByteBuffer.allocate(BLOCK);  
    /*發(fā)送數(shù)據(jù)緩沖區(qū)*/ 
    private  ByteBuffer receivebuffer = ByteBuffer.allocate(BLOCK);  
    private  Selector selector;  
 
    public NIOServer(int port) throws IOException {  
        // 打開服務(wù)器套接字通道  
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();  
        // 服務(wù)器配置為非阻塞  
        serverSocketChannel.configureBlocking(false);  
        // 檢索與此通道關(guān)聯(lián)的服務(wù)器套接字  
        ServerSocket serverSocket = serverSocketChannel.socket();  
        // 進(jìn)行服務(wù)的綁定  
        serverSocket.bind(new InetSocketAddress(port));  
        // 通過open()方法找到Selector  
        selector = Selector.open();  
        // 注冊到selector，等待連接  
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);  
        System.out.println("Server Start----8888:");  
    }  
 
 
    // 監(jiān)聽  
    private void listen() throws IOException {  
        while (true) {  
            // 選擇一組鍵，并且相應(yīng)的通道已經(jīng)打開  
            selector.select();  
            // 返回此選擇器的已選擇鍵集。  
            Set<SelectionKey> selectionKeys = selector.selectedKeys();  
            Iterator<SelectionKey> iterator = selectionKeys.iterator();  
            while (iterator.hasNext()) {          
                SelectionKey selectionKey = iterator.next();  
                iterator.remove();  
                handleKey(selectionKey);  
            }  
        }  
    }  
 
    // 處理請求  
    private void handleKey(SelectionKey selectionKey) throws IOException {  
        // 接受請求  
        ServerSocketChannel server = null;  
        SocketChannel client = null;  
        String receiveText;  
        String sendText;  
        int count=0;  
        // 測試此鍵的通道是否已準(zhǔn)備好接受新的套接字連接。  
        if (selectionKey.isAcceptable()) {  
            // 返回為之創(chuàng)建此鍵的通道。  
            server = (ServerSocketChannel) selectionKey.channel();  
            // 接受到此通道套接字的連接。  
            // 此方法返回的套接字通道（如果有）將處于阻塞模式。  
            client = server.accept();  
            // 配置為非阻塞  
            client.configureBlocking(false);  
            // 注冊到selector，等待連接  
            client.register(selector, SelectionKey.OP_READ);  
        } else if (selectionKey.isReadable()) {  
            // 返回為之創(chuàng)建此鍵的通道。  
            client = (SocketChannel) selectionKey.channel();  
            //將緩沖區(qū)清空以備下次讀取  
            receivebuffer.clear();  
            //讀取服務(wù)器發(fā)送來的數(shù)據(jù)到緩沖區(qū)中  
            count = client.read(receivebuffer);   
            if (count > 0) {  
                receiveText = new String( receivebuffer.array(),0,count);  
                System.out.println("服務(wù)器端接受客戶端數(shù)據(jù)--:"+receiveText);  
                client.register(selector, SelectionKey.OP_WRITE);  
            }  
        } else if (selectionKey.isWritable()) {  
            //將緩沖區(qū)清空以備下次寫入  
            sendbuffer.clear();  
            // 返回為之創(chuàng)建此鍵的通道。  
            client = (SocketChannel) selectionKey.channel();  
            sendText="message from server--" + flag++;  
            //向緩沖區(qū)中輸入數(shù)據(jù)  
            sendbuffer.put(sendText.getBytes());  
             //將緩沖區(qū)各標(biāo)志復(fù)位,因?yàn)橄蚶锩鎝ut了數(shù)據(jù)標(biāo)志被改變要想從中讀取數(shù)據(jù)發(fā)向服務(wù)器,就要復(fù)位  
            sendbuffer.flip();  
            //輸出到通道  
            client.write(sendbuffer);  
            System.out.println("服務(wù)器端向客戶端發(fā)送數(shù)據(jù)--："+sendText);  
            client.register(selector, SelectionKey.OP_READ);  
        }  
    }  
 
    /**  
     * @param args  
     * @throws IOException  
     */ 
    public static void main(String[] args) throws IOException {  
        // TODO Auto-generated method stub  
        int port = 8888;  
        NIOServer server = new NIOServer(port);  
        server.listen();  
    }  
} 

Java代碼：

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.util.Iterator;  
import java.util.Set;  
 
public class NIOClient {  
 
    /*標(biāo)識數(shù)字*/ 
    private static int flag = 0;  
    /*緩沖區(qū)大小*/ 
    private static int BLOCK = 4096;  
    /*接受數(shù)據(jù)緩沖區(qū)*/ 
    private static ByteBuffer sendbuffer = ByteBuffer.allocate(BLOCK);  
    /*發(fā)送數(shù)據(jù)緩沖區(qū)*/ 
    private static ByteBuffer receivebuffer = ByteBuffer.allocate(BLOCK);  
    /*服務(wù)器端地址*/ 
    private final static InetSocketAddress SERVER_ADDRESS = new InetSocketAddress(  
            "localhost", 1111);  
 
    public static void main(String[] args) throws IOException {  
        // TODO Auto-generated method stub  
        // 打開socket通道  
        SocketChannel socketChannel = SocketChannel.open();  
        // 設(shè)置為非阻塞方式  
        socketChannel.configureBlocking(false);  
        // 打開選擇器  
        Selector selector = Selector.open();  
        // 注冊連接服務(wù)端socket動(dòng)作  
        socketChannel.register(selector, SelectionKey.OP_CONNECT);  
        // 連接  
        socketChannel.connect(SERVER_ADDRESS);  
        // 分配緩沖區(qū)大小內(nèi)存  
          
        Set<SelectionKey> selectionKeys;  
        Iterator<SelectionKey> iterator;  
        SelectionKey selectionKey;  
        SocketChannel client;  
        String receiveText;  
        String sendText;  
        int count=0;  
 
        while (true) {  
            //選擇一組鍵，其相應(yīng)的通道已為 I/O 操作準(zhǔn)備就緒。  
            //此方法執(zhí)行處于阻塞模式的選擇操作。  
            selector.select();  
            //返回此選擇器的已選擇鍵集。  
            selectionKeys = selector.selectedKeys();  
            //System.out.println(selectionKeys.size());  
            iterator = selectionKeys.iterator();  
            while (iterator.hasNext()) {  
                selectionKey = iterator.next();  
                if (selectionKey.isConnectable()) {  
                    System.out.println("client connect");  
                    client = (SocketChannel) selectionKey.channel();  
                    // 判斷此通道上是否正在進(jìn)行連接操作。  
                    // 完成套接字通道的連接過程。  
                    if (client.isConnectionPending()) {  
                        client.finishConnect();  
                        System.out.println("完成連接!");  
                        sendbuffer.clear();  
                        sendbuffer.put("Hello,Server".getBytes());  
                        sendbuffer.flip();  
                        client.write(sendbuffer);  
                    }  
                    client.register(selector, SelectionKey.OP_READ);  
                } else if (selectionKey.isReadable()) {  
                    client = (SocketChannel) selectionKey.channel();  
                    //將緩沖區(qū)清空以備下次讀取  
                    receivebuffer.clear();  
                    //讀取服務(wù)器發(fā)送來的數(shù)據(jù)到緩沖區(qū)中  
                    count=client.read(receivebuffer);  
                    if(count>0){  
                        receiveText = new String( receivebuffer.array(),0,count);  
                        System.out.println("客戶端接受服務(wù)器端數(shù)據(jù)--:"+receiveText);  
                        client.register(selector, SelectionKey.OP_WRITE);  
                    }  
 
                } else if (selectionKey.isWritable()) {  
                    sendbuffer.clear();  
                    client = (SocketChannel) selectionKey.channel();  
                    sendText = "message from client--" + (flag++);  
                    sendbuffer.put(sendText.getBytes());  
                     //將緩沖區(qū)各標(biāo)志復(fù)位,因?yàn)橄蚶锩鎝ut了數(shù)據(jù)標(biāo)志被改變要想從中讀取數(shù)據(jù)發(fā)向服務(wù)器,就要復(fù)位  
                    sendbuffer.flip();  
                    client.write(sendbuffer);  
                    System.out.println("客戶端向服務(wù)器端發(fā)送數(shù)據(jù)--："+sendText);  
                    client.register(selector, SelectionKey.OP_READ);  
                }  
            }  
            selectionKeys.clear();  
        }  
    }  
} 

個(gè)人感覺，JAVA NIO的操作時(shí)麻煩了不少，但是無疑這樣做效率會(huì)得到很大的提升。

原文鏈接：http://xm-king.iteye.com/blog/766330

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