练习UDPEchoServer1

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

public class UDPEchoServer1 {
    // 对于一个服务器程序来说, 核心流程也是要分成两步.
    // 1. 进行初始化操作 (实例化 Socket 对象)
    // 2. 进入主循环, 接受并处理请求. (主循环就是一个 "死循环")
    //   a) 读取数据并解析
    //   b) 根据请求计算响应
    //   c) 把响应结果写回到客户端.
    private DatagramSocket socket = null;

    public UDPEchoServer1(int port) throws SocketException {
        socket = new DatagramSocket(port);
    }

    public void start() throws IOException {
        System.out.println("服务器启动");
        while (true) {
            DatagramPacket requestPacket = new DatagramPacket(new byte[4096] , 4096);
            socket.receive(requestPacket);
            String request = new String(requestPacket.getData(),0,requestPacket.getLength()).trim();

            String response = process(request);

            DatagramPacket responsePacket = new DatagramPacket(response.getBytes(), response.getBytes().length, requestPacket.getSocketAddress());
            socket.send(responsePacket);
        }
    }

    private String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        UDPEchoServer1 server = new UDPEchoServer1(9090);
        server.start();
    }
}