我正在使用Netbeans IDE尝试在客户端和服务器之间建立UDP连接,这是一个简单的程序,UDPClient将字符串发送到UDPServer,服务器将字符串大写并将其发送回客户端.我做了客户端和服务器端在一个单独的项目中.

我的客户端UDPClient的类代码：

package udpclient;

import java.io.*;

import java.net.*;

public class UDPClient {

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

//get input from user

BufferedReader user_in = new BufferedReader(

new InputStreamReader(System.in));

//create udp socket connection

DatagramSocket socket = new DatagramSocket();

//creat buffers to process data

byte[] inData = new byte[1024];

byte[] outData = new byte[1024];

//get ip destination wanted

InetAddress IP = InetAddress.getByName("localhost");

//read data from user

System.out.println("Enter Data to send to server: ");

outData = user_in.readLine().getBytes();

/*

* make pkts for interaction

*/

//send pkts

DatagramPacket sendPkt = new DatagramPacket(outData, outData.length, IP, 9876);

socket.send(sendPkt);

//receive pkts

DatagramPacket recievePkt = new DatagramPacket(inData, inData.length);

socket.receive(recievePkt);

System.out.println("Replay from Server: "+recievePkt.getData());

}

}

和我的服务器端类UDPServer：

package udpserver;

import java.io.*;

import java.net.*;

public class UDPServer {

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

// TODO code application logic

//connection

DatagramSocket socket = new DatagramSocket();

//pkt buffers

byte[] inServer = new byte[1024];

byte[] outServer = new byte[1024];

//receive pkt

DatagramPacket rcvPkt = new DatagramPacket(inServer,inServer.length);

socket.receive(rcvPkt);

//display receive

System.out.println("Packet Received!");

//retrive pkt info to send response to same sender

InetAddress IP = rcvPkt.getAddress();

int port = rcvPkt.getPort();

//process data

String temp = new String(rcvPkt.getData());

temp = temp.toUpperCase();

outServer = temp.getBytes();

//send response packet to sender

DatagramPacket sndPkt = new DatagramPacket(outServer, outServer.length, IP, port);

socket.send(sndPkt);

}

}

make计数程序正常运行并且不输出错误.服务器根本没有收到数据包,它没有与客户端交互.为什么会这样？

解决方法:

您尚未在服务器中指定任何侦听端口,因此服务器会侦听随机可用端口.

在服务器端试试这个

DatagramSocket socket = new DatagramSocket(9876);

标签：udp,java,sockets,netbeans,network-programming

来源： https://codeday.me/bug/20190609/1205075.html