Can'；在java中无法从UDP服务器接收正确的消息

我正在尝试使用udp客户端向udp服务器发送消息，并将消息发送回客户端，其中包含有关接收消息的各种元数据。 我有两门课：

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

public class UdpDateClient {
    public static void main(String[] args) throws IOException {
        String host = "localhost";
        if (args.length > 0)
            host = args[0];
        // get a datagram socket on any available port
        try {
            DatagramSocket socket = new DatagramSocket();
            // send request
            byte[] buf = new byte[2048];
            buf="hi it's Max".getBytes();
            InetAddress address = InetAddress.getByName(host);
            DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 4445);
            socket.send(packet);
            // get response
            packet = new DatagramPacket(buf, buf.length);
            socket.receive(packet);
            // display response
            buf = packet.getData();
            int len = packet.getLength();
            String received = (new String(buf)).substring(0, len);
            System.out.println("From server: " + received);
            socket.close();
        } catch (SocketException e) {
            e.printStackTrace();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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我在客户端得到的只是服务器发送的消息的前11个字节：

客户端：

来自服务器：客户端是我

服务器端：

服务器就绪

收到来自客户的数据包：嗨，我是Max

要从服务器发送的buf：接收到客户端消息：hi it's Max

收到日期：2015年8月14日星期五16:00:20 IDT

基本长度=2116

如您所见，客户端从服务器接收到的消息在11个字符后被剪切

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我做错了什么？

问题在于行

buf=“hi it's Max.”getBytes（）。
这里您将缓冲区长度设置为11。
您的客户端代码应该如下所示

            DatagramSocket socket = new DatagramSocket();
            // send request
            byte[] buf = "hi it's Max".getBytes();
            InetAddress address = InetAddress.getByName(host);
            DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 4445);
            socket.send(packet);
            // get response
            buf = new byte[2048];
            packet = new DatagramPacket(buf, buf.length);
            socket.receive(packet);
            // display response
            buf = packet.getData();
            int len = packet.getLength();
            String received = (new String(buf)).substring(0, len);
            System.out.println("From server: " + received);
            socket.close();

在此之后，
buf.长度将是11而不是2048

在你回来的路上

packet = new DatagramPacket(buf, buf.length);
socket.receive(packet);

将只接收11个字节，因为
buf.length
为11。将第一个块更改为

byte[] buf = new byte[2048];
System.arraycopy("hi it's Max".getBytes(), 0, buf, 0, 11);

packet = new DatagramPacket(buf, buf.length);
socket.receive(packet);

byte[] buf = new byte[2048];
System.arraycopy("hi it's Max".getBytes(), 0, buf, 0, 11);