UDP协议通讯,服务器短和客户端无法绑定同一个端口？

import java.net.*;

public class UDPServer {
    private static final int PORT = 5000;
    private DatagramSocket dataSocket;
    private DatagramPacket dataPacket;
    private byte receiveByte[];
    private String receiveStr;

    public UDPServer() {
        Init();
    }

    public void Init() {
        try {
            dataSocket = new DatagramSocket(PORT);
            receiveByte = new byte[1024];
            dataPacket = new DatagramPacket(receiveByte, receiveByte.length);
            receiveStr = "";
            int i = 0;
            while (i == 0)// 无数据，则循环

            {
                dataSocket.receive(dataPacket);
                i = dataPacket.getLength();
                // 接收数据

                if (i > 0) {
                    // 指定接收到数据的长度,可使接收数据正常显示,开始时很容易忽略这一点

                    receiveStr = new String(receiveByte, 0, dataPacket.getLength());
                    System.out.println(receiveStr);
                    i = 0;// 循环接收

                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String args[]) {
        new UDPServer();
    }
}

import java.io.*;
import java.net.*;

public class UDPClient {
    private static final int PORT = 5000;
    private DatagramSocket dataSocket;
    private DatagramPacket dataPacket;
    private byte sendDataByte[];