JAVA+UDP+多线程实现简单聊天

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class ChatRoomByDemo {
    public static void main(String[] args) {
        String host = "127.0.0.1";
        int port = 10086;

        SendThread st = new SendThread(host, port);
        ReceiveThread rt = new ReceiveThread(port); 
        Thread t1 = new Thread(st);
        Thread t2 = new Thread(rt);

        t1.start();
        t2.start();
    }
}

class ReceiveThread implements Runnable {
    private int port;
    private DatagramSocket dsSocket;
    private String endStr = "886";

    /**
     * @param endStr the endStr to set
     */
    public void setEndStr(String endStr) {
        this.endStr = endStr;
    }

    public ReceiveThread(int port) {
        this.port = port;
    }

    @Override
    public void run() {
        try {
            dsSocket = new DatagramSocket(port);
            while (true) {
                byte[] bys = new byte[1024];
                DatagramPacket dPacket = new DatagramPacket(bys, bys.length);
                dsSocket.receive(dPacket);

                String ip = dPacket.getAddress().getHostAddress();
                String msg = new String(dPacket.getData(), 0, dPacket.getLength());
                System.out.println("receive("+ip + "):" + msg);
                if (msg.equals(endStr)) {
                    break;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (dsSocket != null) {
                dsSocket.close();
                System.out.println("socket close");
            }
        }

    }
}

class SendThread implements Runnable {
    private String host;
    private int port;
    private DatagramSocket dsSocket;
    private String endStr = "886";

    /**
     * @param endStr the endStr to set
     */
    public void setEndStr(String endStr) {
        this.endStr = endStr;
    }

    public SendThread(String host, int port) {
        this.host = host;
        this.port = port;
    }

    @Override
    public void run() {
        try {
            dsSocket = new DatagramSocket();
            System.out.print("输入聊天内容:");
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            String msg = null;

            InetAddress address = InetAddress.getByName(host);

            while ((msg = br.readLine()) != null) {
                byte[] bys = msg.getBytes();
                DatagramPacket dp = new DatagramPacket(bys, bys.length, address, port);
                dsSocket.send(dp);
                System.out.println("send:"+msg);
                if (endStr.equals(msg)) {
                    break;
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (dsSocket != null) {
                dsSocket.close();
            }
        }
    }
}