自己做的UDP客户端和服务器端

import java.io.*; import java.net.*; class UDPServer { public static void main(String args[]) throws Exception { DatagramSocket serverSocket = new DatagramSocket(9876); 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()); //对字符串中的s计数 char string[]; int num = 0; string = sentence.toCharArray(); for (int i = 0; i < sentence.length(); i++) if (string[i] == 's') num++; String num1 = String.valueOf(num); sendData = num1.getBytes(); // InetAddress IPAddress = receivePacket.getAddress(); int port = receivePacket.getPort(); DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port); serverSocket.send(sendPacket); } } }