http://www.cnblogs.com/likwo/archive/2010/06/29/1767814.html
NIO Selector示意圖:
客戶端代碼:
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;
/**
* NIO TCP 客戶端
*
* @date 2010-2-3
* @time 下午03:33:26
* @version 1.00
*/
public class TCPClient{
// 信道選擇器
private Selector selector;
// 與服務器通信的信道
SocketChannel socketChannel;
// 要連接的服務器Ip地址
private String hostIp;
// 要連接的遠程服務器在監聽的端口
private int hostListenningPort;
/**
* 構造函數
* @param HostIp
* @param HostListenningPort
* @throws IOException
*/
public TCPClient(String HostIp,int HostListenningPort)throws IOException{
this.hostIp=HostIp;
this.hostListenningPort=HostListenningPort;
initialize();
}
/**
* 初始化
* @throws IOException
*/
private void initialize() throws IOException{
// 打開監聽信道並設置爲非阻塞模式
socketChannel=SocketChannel.open(new InetSocketAddress(hostIp, hostListenningPort));
socketChannel.configureBlocking(false);
// 打開並註冊選擇器到信道
selector = Selector.open();
socketChannel.register(selector, SelectionKey.OP_READ);
// 啓動讀取線程
new TCPClientReadThread(selector);
}
/**
* 發送字符串到服務器
* @param message
* @throws IOException
*/
public void sendMsg(String message) throws IOException{
ByteBuffer writeBuffer=ByteBuffer.wrap(message.getBytes("UTF-16"));
socketChannel.write(writeBuffer);
}
public static void main(String[] args) throws IOException{
TCPClient client=new TCPClient("192.168.0.1",1978);
client.sendMsg("你好!Nio!醉裏挑燈看劍,夢迴吹角連營");
}
}
客戶端讀取線程代碼:
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
public class TCPClientReadThread implements Runnable{
private Selector selector;
public TCPClientReadThread(Selector selector){
this.selector=selector;
new Thread(this).start();
}
public void run() {
try {
while (selector.select() > 0) {
// 遍歷每個有可用IO操作Channel對應的SelectionKey
for (SelectionKey sk : selector.selectedKeys()) {
// 如果該SelectionKey對應的Channel中有可讀的數據
if (sk.isReadable()) {
// 使用NIO讀取Channel中的數據
SocketChannel sc = (SocketChannel) sk.channel();
ByteBuffer buffer = ByteBuffer.allocate(1024);
sc.read(buffer);
buffer.flip();
// 將字節轉化爲爲UTF-16的字符串
String receivedString=Charset.forName("UTF-16").newDecoder().decode(buffer).toString();
// 控制檯打印出來
System.out.println("接收到來自服務器"+sc.socket().getRemoteSocketAddress()+"的信息:"+receivedString);
// 爲下一次讀取作準備
sk.interestOps(SelectionKey.OP_READ);
}
// 刪除正在處理的SelectionKey
selector.selectedKeys().remove(sk);
}
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
服務器端代碼:
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.util.Iterator;
/**
* TCP服務器端
*
* @date 2010-2-3
* @time 上午08:39:48
* @version 1.00
*/
public class TCPServer{
// 緩衝區大小
private static final int BufferSize=1024;
// 超時時間,單位毫秒
private static final int TimeOut=3000;
// 本地監聽端口
private static final int ListenPort=1978;
public static void main(String[] args) throws IOException{
// 創建選擇器
Selector selector=Selector.open();
// 打開監聽信道
ServerSocketChannel listenerChannel=ServerSocketChannel.open();
// 與本地端口綁定
listenerChannel.socket().bind(new InetSocketAddress(ListenPort));
// 設置爲非阻塞模式
listenerChannel.configureBlocking(false);
// 將選擇器綁定到監聽信道,只有非阻塞信道纔可以註冊選擇器.並在註冊過程中指出該信道可以進行Accept操作
listenerChannel.register(selector, SelectionKey.OP_ACCEPT);
// 創建一個處理協議的實現類,由它來具體操作
TCPProtocol protocol=new TCPProtocolImpl(BufferSize);
// 反覆循環,等待IO
while(true){
// 等待某信道就緒(或超時)
if(selector.select(TimeOut)==0){
System.out.print("獨自等待.");
continue;
}
// 取得迭代器.selectedKeys()中包含了每個準備好某一I/O操作的信道的SelectionKey
Iterator<SelectionKey> keyIter=selector.selectedKeys().iterator();
while(keyIter.hasNext()){
SelectionKey key=keyIter.next();
try{
if(key.isAcceptable()){
// 有客戶端連接請求時
protocol.handleAccept(key);
}
if(key.isReadable()){
// 從客戶端讀取數據
protocol.handleRead(key);
}
if(key.isValid() && key.isWritable()){
// 客戶端可寫時
protocol.handleWrite(key);
}
}
catch(IOException ex){
// 出現IO異常(如客戶端斷開連接)時移除處理過的鍵
keyIter.remove();
continue;
}
// 移除處理過的鍵
keyIter.remove();
}
}
}
}
協議接口代碼:
import java.io.IOException;
import java.nio.channels.SelectionKey;
/**
* TCPServerSelector與特定協議間通信的接口
*
* @date 2010-2-3
* @time 上午08:42:42
* @version 1.00
*/
public interface TCPProtocol{
/**
* 接收一個SocketChannel的處理
* @param key
* @throws IOException
*/
void handleAccept(SelectionKey key) throws IOException;
/**
* 從一個SocketChannel讀取信息的處理
* @param key
* @throws IOException
*/
void handleRead(SelectionKey key) throws IOException;
/**
* 向一個SocketChannel寫入信息的處理
* @param key
* @throws IOException
*/
void handleWrite(SelectionKey key) throws IOException;
}
協議實現類代碼:
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Date;
/**
* TCPProtocol的實現類
*
* @date 2010-2-3
* @time 上午08:58:59
* @version 1.00
*/
public class TCPProtocolImpl implements TCPProtocol{
private int bufferSize;
public TCPProtocolImpl(int bufferSize){
this.bufferSize=bufferSize;
}
public void handleAccept(SelectionKey key) throws IOException {
SocketChannel clientChannel=((ServerSocketChannel)key.channel()).accept();
clientChannel.configureBlocking(false);
clientChannel.register(key.selector(), SelectionKey.OP_READ,ByteBuffer.allocate(bufferSize));
}
public void handleRead(SelectionKey key) throws IOException {
// 獲得與客戶端通信的信道
SocketChannel clientChannel=(SocketChannel)key.channel();
// 得到並清空緩衝區
ByteBuffer buffer=(ByteBuffer)key.attachment();
buffer.clear();
// 讀取信息獲得讀取的字節數
long bytesRead=clientChannel.read(buffer);
if(bytesRead==-1){
// 沒有讀取到內容的情況
clientChannel.close();
}
else{
// 將緩衝區準備爲數據傳出狀態
buffer.flip();
// 將字節轉化爲爲UTF-16的字符串
String receivedString=Charset.forName("UTF-16").newDecoder().decode(buffer).toString();
// 控制檯打印出來
System.out.println("接收到來自"+clientChannel.socket().getRemoteSocketAddress()+"的信息:"+receivedString);
// 準備發送的文本
String sendString="你好,客戶端. @"+new Date().toString()+",已經收到你的信息"+receivedString;
buffer=ByteBuffer.wrap(sendString.getBytes("UTF-16"));
clientChannel.write(buffer);
// 設置爲下一次讀取或是寫入做準備
key.interestOps(SelectionKey.OP_READ | SelectionKey.OP_WRITE);
}
}
public void handleWrite(SelectionKey key) throws IOException {
// do nothing
}
}
http://www.blogjava.net/longturi/archive/2010/02/03/311820.html
另外一篇比較好的文章
http://www.oschina.net/question/54100_33530