UDP 数据报中发送的消息未经过净化？

我的代码如下。一切都按照我想要的方式进行，但是当我的消息收到时，它们的末尾有很多框，有点像这样“消息：你好▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ ▀▀▀▀▀▀▀" 如何才能让接收和打印的内容仅为“Message: hello”？我非常感谢任何帮助。

import java.io.*;
import java.net.*;

public class UDPChat {

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

        new UDPChat();
    }


    public UDPChat() {
        try {
            runChat();
        } catch (Exception e) {
        }}

    public void runChat() throws InterruptedException {
        Sender sender = new Sender();
        Receiver receiver = new Receiver();
        sender.start();
        receiver.start();
        sender.join();
        receiver.join();
    }

    class Receiver extends Thread {
        public void run() {
            try {
                DatagramSocket serverSocket = new DatagramSocket(9876);
                byte[] receiveData = new byte[1024];
                while (true) {
                    DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
                    serverSocket.receive(receivePacket);
                    String sentence = new String(receivePacket.getData());
                    System.out.println("Message: " + sentence);
                }
            } catch (IOException e) {
            }
        }
    }

    class Sender extends Thread {
        public void run() {
            try {
                DatagramSocket clientSocket = new DatagramSocket();
                InetAddress IPAddress = InetAddress.getByName("localhost");
                byte[] sendData = new byte[1024];
                while (true) {
                BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
                String message = inFromUser.readLine();
                sendData = message.getBytes();

                DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 9876);
                clientSocket.send(sendPacket);
                }
            } catch (IOException e) {
            }
        }
    }

}

String sentence = new String(receivePacket.getData());

通常的问题。忽略数据报长度。修复如下：

String sentence = new String(receivePacket.getData(), receivePacket.getOffset(), receivePacket.getLength());