JAVA服务器端，如何开启同一个端口发送包

[weixin_44835628]

我用udp多线程做了一个服务器，但是这个时候想用接收的端口2020来给指定的ip和端口发送一个包。这时总是遇到重复占用的问题。 请问能否临时关闭UDP服务器的监听，来完成这个发送过程？我想发送完了再打开监听。
或者我想java是不是有什么中断（多线程）的机制来着。中断后能让之前打开的端口也回复正常，可以执行新的程序重新开端口，执行完了再退出中断？

下面附上服务器代码：
-----
tart.java
-----

package com.udp;
import java.io.IOException;
import java.net.DatagramSocket;

public class Start {
	 public static void main (String[] args) throws IOException {
		 DatagramSocket dsReceive = new DatagramSocket(2020);
		 UDPServer rt= new UDPServer(dsReceive);
		 Thread t1 = new Thread(rt);
		 t1.start();
	 }
}

------
UDPServer.class
------

package com.udp;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class UDPServer implements Runnable {
	private DatagramSocket socket;
	// 创建接收和发送UDP的Socket实例
	public UDPServer(DatagramSocket socket) {
		this.socket = socket;
	}
	@Override
	public void run() {
		try {
			while (true) {
				byte[] data = new byte[1024];
            	DatagramPacket request = new DatagramPacket(data,data.length);
                socket.receive(request); //接受UDP数据包
            	System.out.println("Addr："+request.getAddress()+"port："+request.getPort());
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} // 接受UDP数据包
	}
}

[weixin_44835628]

自己搞定了。 需要使用NIO的非堵塞方式进行。 为了同时做其他事，做了一个多线程，下面是主程序

package com.tcptest;

import java.io.IOException;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.charset.Charset;
import java.util.Iterator;

import com.tcptest.Server;


public class start {

    static DatagramChannel channel;  
    static Selector selector;  

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

    	try  
        {  
            // 打开一个UDP Channel  
            channel = DatagramChannel.open();
            
            channel.socket().setReuseAddress(true);//允许绑定同一个端口
              
            // 设定为非阻塞通道  
            channel.configureBlocking(false);  
            // 绑定端口  
            channel.socket().bind(new InetSocketAddress(8080));  
  
            // 打开一个选择器  
            selector = Selector.open();  
            channel.register(selector, SelectionKey.OP_READ);  
        } catch (Exception e)  
        {  
            e.printStackTrace();  
        }
    	
		 
		 Server rt= new Server(selector);
		 Thread t1 = new Thread(rt);
		 t1.start();
		 
		 System.out.println("请输入:");
		 while(true){
             char val = (char)System.in.read();
                 System.out.println("Your char is :" + val + "\r");
         }

	 }

下面是Server.class

package com.tcptest;

import java.net.DatagramSocket;
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.Iterator;

public class Server implements Runnable {
	
    DatagramChannel channel;  
    Selector selector;  
 
	public Server(Selector selector) {
		this.selector = selector;
	}
	
	@Override
	public void run() {
		 
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);  
        
        while (true)  
        {  
            try  
            {  
                // 进行选择  
                int n = selector.select();  
                if (n > 0)  
                {  
                    // 获取以选择的键的集合  
                    Iterator iterator = selector.selectedKeys().iterator();  
  
                    while (iterator.hasNext())  
                    {  
                        SelectionKey key = (SelectionKey) iterator.next();  
  
                        // 必须手动删除  
                        iterator.remove();  
                        key.isWritable();
                        if (key.isReadable())  
                        {  
                            DatagramChannel datagramChannel = (DatagramChannel) key  
                                    .channel();  
  
                            byteBuffer.clear();  
                            // 读取  
                            InetSocketAddress address = (InetSocketAddress) datagramChannel  
                                    .receive(byteBuffer);  

                            int length = byteBuffer.position();
                            int i;
                            byte rec[]=new byte[length];
                            for (i=0;i<length;i++)
                            	{
                            	rec[i]=byteBuffer.get(i);
                            	}
                            // 删除缓冲区中的数据  
                            byteBuffer.clear();  
                            
                            byteBuffer.put(rec);  
  
                            byteBuffer.flip();
                         
                            // 发送数据  
                            datagramChannel.send(byteBuffer, address);  
                        }  
                    }  
                }  
            } catch (Exception e)  
            {  
                e.printStackTrace();  
            }  
        }  
  
        
		
	}
	
	

}

[weixin_44835628]

自己不能结自己贴啊