我有 2 节课
头等舱
import java.io.IOException;
import java.net.*;
public class Udp {
DatagramSocket socket = null;
DatagramPacket inPacket = null; // recieving packet
DatagramPacket outPacket = null; // sending packet
byte[] inBuf, outBuf;
InetAddress source_address = null;
public String Hasil = null;
String msg;
final int PORT = 8888;
public void received() {
try {
socket = new DatagramSocket(PORT);
while (true) {
System.out.println("Waiting for client...");
// Receiving datagram from client
inBuf = new byte[256];
inPacket = new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
// Extract data, ip and port
int source_port = inPacket.getPort();
source_address = inPacket.getAddress();
msg = new String(inPacket.getData(), 0, inPacket.getLength());
// System.out.println("Client " + source_address + ":" + msg);
Hasil = msg;
// Send back to client as an echo
msg = reverseString(msg.trim());
outBuf = msg.getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length,
source_address, source_port);
socket.send(outPacket);
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
System.out.println("Client " + source_address + ":" + msg);
}
private static String reverseString(String input) {
StringBuilder buf = new StringBuilder(input);
return buf.reverse().toString();
}}
和二等
public class main {
public static void main(String[] args) {
Udp u = new Udp();
u.received();
System.out.println(u.Hasil + " " + u.source_address);
}
}
为什么当我运行这个 porgram 时,udp 是启动的,但是 String Hasil 没有启动,我如何在语句 While (true) 中获取 String Hasil?