Java NIO -- DatagramChannel

Java NIO中的DatagramChannel是一个能收发UDP包的通道。
操作步骤：
打开 DatagramChannel
接收/发送数据

代码举例：

package com.soyoungboy.nio;

import java.io.IOException;

import java.net.InetSocketAddress;

import java.nio.ByteBuffer;

import java.nio.channels.DatagramChannel;

import java.nio.channels.SelectionKey;

import java.nio.channels.Selector;

import java.util.Date;

import java.util.Iterator;

import java.util.Scanner;

import org.junit.Test;

public class TestDatagramChannel {

    @Test

    public void send() throws IOException{

        DatagramChannel dc = DatagramChannel.open();

        dc.configureBlocking(false);

        ByteBuffer buf = ByteBuffer.allocate(1024);

        Scanner scan = new Scanner(System.in);

        while(scan.hasNext()){

            String str = scan.next();

            buf.put((new Date().toString() + ":\n" + str).getBytes());

            buf.flip();

            dc.send(buf, new InetSocketAddress("127.0.0.1", 9898));

            buf.clear();

        }

        dc.close();

    }

    @Test

    public void receive() throws IOException{

        DatagramChannel dc = DatagramChannel.open();

        dc.configureBlocking(false);

        dc.bind(new InetSocketAddress(9898));

        Selector selector = Selector.open();

        dc.register(selector, SelectionKey.OP_READ);

        while(selector.select() > 0){

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

            while(it.hasNext()){

                SelectionKey sk = it.next();

                if(sk.isReadable()){

                    ByteBuffer buf = ByteBuffer.allocate(1024);

                    dc.receive(buf);

                    buf.flip();

                    System.out.println(new String(buf.array(), 0, buf.limit()));

                    buf.clear();

                }

            }

            it.remove();

        }

    }

}