客服端響應服務端時數(shù)據(jù)報創(chuàng)建不用傳IP和端口嗎？ 為什么是DatagramPacket packe2=new DatagramPacket(data, data.length);

而不是這樣寫呢？DatagramPacket packet=new DatagramPacket(data, data.length, address, port);

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public class UDPClient {

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

/*

* 向服務器端發(fā)送數(shù)據(jù)

*/

//1.定義服務器的地址、端口號、數(shù)據(jù)

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

int port=8800;

byte[] data="用戶名：admin;密碼：123".getBytes();

//2.創(chuàng)建數(shù)據(jù)報，包含發(fā)送的數(shù)據(jù)信息

DatagramPacket packet=new DatagramPacket(data, data.length, address, port);

//3.創(chuàng)建DatagramSocket對象

DatagramSocket socket=new DatagramSocket();

//4.向服務器端發(fā)送數(shù)據(jù)報

socket.send(packet);

/*

* 接收服務器端響應的數(shù)據(jù)

*/

//1.創(chuàng)建數(shù)據(jù)報，用于接收服務器端響應的數(shù)據(jù)

byte[] data2=new byte[1024];

DatagramPacket packet2=new DatagramPacket(data2, data2.length);

//2.接收服務器響應的數(shù)據(jù)

socket.receive(packet2);

//3.讀取數(shù)據(jù)

String reply=new String(data2, 0, packet2.getLength());

System.out.println("我是客戶端，服務器說："+reply);

//4.關(guān)閉資源

socket.close();