【Java nio】 NonBlocking NIO

package com.slp.nio;

import org.junit.Test;

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.time.LocalDateTime;
import java.util.Date;
import java.util.Iterator;
import java.util.Scanner;

/**
 * Created by sanglp on 2017/3/2.
 * 一、使用NIO完成网络通信的三个核心
 * 1、通道：负责连接
 *     |--java.nio.channels.channel接口
 *        |--SelectableChannel
 *           |--SocketChannel
 *           |--ServerSocketChannel
 *           |--DatagramChannel
 *
 *           |--Pipe.SinkChannel
 *           |--Pipe.SourceChannel
 * 2、缓冲区：负责数据的存取
 * 3、选择器：是SelectableChannel的多路复用器，用于监控SelectableChannel的IO状况
 *
 */
public class TestNonBlockingNIO {

    @Test
    public void client() throws IOException {
        //获取通道
        SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1",9898));
        //切换为非阻塞模式
      socketChannel.configureBlocking(false);
        //分配缓冲区
        ByteBuffer buf = ByteBuffer.allocate(1024);
        //发送数据给服务端

        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()){
            String str = scanner.next();
            buf.put((new Date().toString()+"\n"+str).getBytes());
            buf.flip();
            socketChannel.write(buf);
            buf.clear();
        }


        //关闭通道
        socketChannel.close();

    }

    @Test
    public void server() throws IOException {
        //获取通道
       ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        //切换非阻塞模式
        serverSocketChannel.configureBlocking(false);
        //绑定连接
        serverSocketChannel.bind(new InetSocketAddress(9898));
        //获取一个选择器
        Selector selector = Selector.open();
        //将通道注册到选择器上 并且指定监听接收事件
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        //轮询式的获取选择器上已经准备就绪的事件
        while (selector.select()>0){
            //获取当前选择器中所有注册的选择键(已就绪的监听事件)
            Iterator<SelectionKey> it = selector.selectedKeys().iterator();
            while (it.hasNext()){
                //获取准备就绪的事件
                SelectionKey sk = it.next();
                //判断具体是什么事件准备就绪
                if(sk.isAcceptable()){
                    //获取额护短连接
                    SocketChannel socketChannel = serverSocketChannel.accept();
                    //切换非阻塞模式
                    socketChannel.configureBlocking(false);
                    //将该通道注册到选择器上
                    socketChannel.register(selector,SelectionKey.OP_READ);
                }else if(sk.isReadable()){
                    //获取当前选择器上读就绪状态的通道
                    SocketChannel socketChannel = (SocketChannel) sk.channel();
                    //读取数据
                    ByteBuffer buffer = ByteBuffer.allocate(1024);
                    int len =0;
                    while ((len=socketChannel.read(buffer))>0){
                        buffer.flip();
                        System.out.println(new String(buffer.array(),0,len));
                        buffer.clear();
                    }
                }
                //取消选择键
                it.remove();
            }
        }
    }
}