package com.nio;

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.Collection;

import java.util.Date;

import java.util.Iterator;

import java.util.Set;

/**

* 创建一个非阻塞的服务器，向客户端返回当前的系统时间

*/

public class SelectorDemo {

public static void main(String[] args) throws IOException {

int ports[]= { 8000,8001,8002,8003,8004 } ;

Selector selector=Selector.open();

for(int port : ports) {

//打开服务器套接字通道

ServerSocketChannel serverSocketChannel=ServerSocketChannel.open();

//服务器配置设置为非阻塞

serverSocketChannel.configureBlocking(false);

ServerSocket serverSocket=serverSocketChannel.socket();

InetSocketAddress inetSocketAddress=new InetSocketAddress(port);

serverSocket.bind(inetSocketAddress);

//注册选择器，相当于使用accept()方法接收

serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT );

System.out.println("服务器运行,在"+port+"端口监听");

}

int keysAdd;

//选择一组键，相当的通道已为IO准备就绪

while ( (keysAdd=selector.select())>0 ) {

//取出全部生成的key

Set<SelectionKey> selectionKeySet=selector.selectedKeys() ;

Iterator<SelectionKey> iterator=selectionKeySet.iterator();

//迭代全部的SelectionKey

while (iterator.hasNext()) {

SelectionKey key=(SelectionKey) iterator.next();

//判断客户端是否已经连接上

if(key.isAcceptable()) {

//通过key获取channel

ServerSocketChannel serverSocketChannel=(ServerSocketChannel) key.channel();

SocketChannel socketChannel=serverSocketChannel.accept();

serverSocketChannel.configureBlocking(false);

ByteBuffer byteBuffer=ByteBuffer.allocate(1024);

byteBuffer.put(( "当前时间为"+new Date() ).getBytes());

byteBuffer.flip();

socketChannel.write(byteBuffer);

socketChannel.close();

}

}

selectionKeySet.clear();

}

}

}