package JavaDemo.IOTest;

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;

/**

* @Author MaoTian

* @Classname NioClient

* @Description TODO

* @Date 下午9:09 2019/8/7

* @Version 1.0

* @Created by mao<tianmao818@qq.com>

*/

public class NioClient {

//管道管理器

private Selector selector;

public NioClient init(String serverIp, int port) throws IOException {

//获取socket通道

SocketChannel channel = SocketChannel.open();

channel.configureBlocking(false);

//获得通道管理器

selector=Selector.open();

//客户端连接服务器，需要调用channel.finishConnect();才能实际完成连接。

channel.connect(new InetSocketAddress(serverIp, port));

//为该通道注册SelectionKey.OP_CONNECT事件

channel.register(selector, SelectionKey.OP_CONNECT);

return this;

}

public void listen() throws IOException{

System.out.println("客户端启动");

//轮询访问selector

while(true){

//选择注册过的io操作的事件(第一次为SelectionKey.OP_CONNECT)

selector.select();

Iterator<SelectionKey> ite = selector.selectedKeys().iterator();

while(ite.hasNext()){

SelectionKey key = ite.next();

//删除已选的key，防止重复处理

ite.remove();

if(key.isConnectable()){

SocketChannel channel=(SocketChannel)key.channel();

//如果正在连接，则完成连接

if(channel.isConnectionPending()){

channel.finishConnect();

}

channel.configureBlocking(false);

//向服务器发送消息

channel.write(ByteBuffer.wrap(new String("send message to server.").getBytes()));

//连接成功后，注册接收服务器消息的事件

channel.register(selector, SelectionKey.OP_READ);

System.out.println("客户端连接成功");

}else if(key.isReadable()){ //有可读数据事件。

SocketChannel channel = (SocketChannel)key.channel();

ByteBuffer buffer = ByteBuffer.allocate(10);

channel.read(buffer);

byte[] data = buffer.array();

String message = new String(data);

System.out.println("recevie message from server:, size:" + buffer.position() + " msg: " + message);

}

}

}

}

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

new NioClient().init("127.0.0.1", 3333).listen();

}

}