[英]Clear Datagram Buffer in Java
所以我從互聯網上獲得了這個簡單的udp客戶端/服務器代碼,並且它有效。 但是,當我輸入比我之前輸入的東西更短的東西時,我會剩下剩下的字符。 例如,如果我先輸入:
kitty
然后輸入:
cat
第二個印刷品如下:
catty
我一直在尋找其他有類似問題的人,其中大部分似乎都是通過清除字節數組來解決的。 但是,如果我嘗試實現他們的答案,它不能解決我的問題。 我需要做什么,並且(可能更重要的是)代碼應該去哪里? 這是代碼:
客戶:
import java.io.*;
import java.net.*;
class UDPClient
{
public static void main(String args[]) throws Exception
{
BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
DatagramSocket clientSocket = new DatagramSocket();
InetAddress IPAddress = InetAddress.getByName("localhost");
byte[] sendData = new byte[1024];
byte[] receiveData = new byte[1024];
String sentence = inFromUser.readLine();
sendData = sentence.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 20700);
clientSocket.send(sendPacket);
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
clientSocket.receive(receivePacket);
String modifiedSentence = new String(receivePacket.getData());
System.out.println("FROM SERVER:" + modifiedSentence);
clientSocket.close();
}
}
服務器:
import java.io.*;
import java.net.*;
import java.util.*;
class UDPServer
{
public static void main(String args[]) throws Exception
{
DatagramSocket serverSocket = new DatagramSocket(21200);
byte[] receiveData = new byte[1024];
byte[] sendData = new byte[1024];
while(true)
{
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
serverSocket.receive(receivePacket);
String sentence = new String( receivePacket.getData(), 0, receivePacket.getLength());
System.out.println("RECEIVED: " + sentence);
InetAddress IPAddress = receivePacket.getAddress();
int port = receivePacket.getPort();
String capitalizedSentence = sentence.toUpperCase();
sendData = capitalizedSentence.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
serverSocket.send(sendPacket);
}
}
}
您不需要清除字節數組,但是您需要通過getLength()
方法在接收之后注意DatagramPacket的長度; 例如:
new String(packet.getData(), packet.getOffset(), packet.getLength());
您在服務器中正確地執行了此操作,但在客戶端中卻沒有。
您還需要在調用receive()
之前重置長度。 否則, DatagramPacket
將繼續縮小到目前為止收到的最小數據包的長度。
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