UDP:消息发送
想发短信：不用连接，需要知道对方地址
发送消息
package UDP;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
//UDP不需要连接服务器
public class UdpClientDemo1 {
public static void main(String[] args) throws Exception {
// 1.创建一个socket
DatagramSocket socket = new DatagramSocket();
// 2.建立一个包
String msg = "你好啊";
// 3.发送给谁
InetAddress localhoost = InetAddress.getByName("localhost");
int port = 9090;
DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, localhoost, port);
// 4.发送包
socket.send(packet);
// 5.关闭流
socket.close();
}
}
接收端
package UDP;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
///等待客户端连接
public class UdpServerDemo1 {
public static void main(String[] args) throws Exception {
// 开放端口
DatagramSocket socket = new DatagramSocket(9090);
// 接收包
byte[] buffer = new byte[1024];
DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
socket.receive(packet); //阻塞接收
System.out.println(packet.getAddress().getHostAddress());
System.out.println(new String(packet.getData(),0,packet.getLength()));
// 关闭连接
socket.close();
}
}
UDP模拟聊天
循环发送消息
package Chat;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.*;
public class UdpSenderDemo1 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(8888);
// 准备数据：控制台读取：System.in
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
while (true) {
String data = reader.readLine();
byte[] datas = data.getBytes();
DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 6666));
socket.send(packet);
if (data.equals("bey")) {
break;
}
}
socket.close();
}
}
循环接收消息
package Chat;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class UdpReceiveDemo1 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(6666);
while (true) {
// 准备接收包裹
byte[] continer = new byte[1024];
DatagramPacket packet = new DatagramPacket(continer, 0, continer.length);
socket.receive(packet); //阻塞式接收包裹
// 断开连接
byte[] data = packet.getData();
String receiveData = new String(data, 0, data.length);
System.out.println(receiveData);
if (receiveData.equals("bey")) {
break;
}
}
socket.close();
}
}
在线咨询：两个人都可以发送，接收
接收端：
package Chat;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
public class TalkReceive implements Runnable{
DatagramSocket socket = null;
private int port;
private String magFrom;
public TalkReceive(int port, String magFrom) {
this.port = port;
this.magFrom = magFrom;
try {
socket = new DatagramSocket(port);
} catch (SocketException e) {
e.printStackTrace();
}
}
public void run() {
while (true) {
try {
// 准备接收包裹
byte[] continer = new byte[1024];
DatagramPacket packet = new DatagramPacket(continer, 0, continer.length);
socket.receive(packet); //阻塞式接收包裹
// 断开连接 bey
byte[] data = packet.getData();
String receiveData = new String(data, 0, data.length);
System.out.println(magFrom + " ：" + receiveData);
if (receiveData.equals("bey")) {
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
socket.close();
}
}
读取：
package Chat;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
public class TalkSend implements Runnable {
DatagramSocket socket = null;
BufferedReader reader = null;
private int fromPort;
private String toIp;
private int toPort;
public TalkSend( int fromPort, String toIp, int toPort) {
this.fromPort = fromPort;
this.toIp = toIp;
this.toPort = toPort;
try {
socket = new DatagramSocket(fromPort);
// 准备数据：控制台读取：System.in
reader = new BufferedReader(new InputStreamReader(System.in));
} catch ( Exception e) {
e.printStackTrace();
}
}
public void run() {
while (true) {
String data = null;
try {
data = reader.readLine();
byte[] datas = data.getBytes();
DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress(this.toIp,this.toPort));
socket.send(packet);
if (data.equals("bey")) {
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
socket.close();
}
}
创建老师线程
package Chat;
public class TalkTeacher {
public static void main(String[] args) {
new Thread(new TalkSend(5555,"localhost",8888)).start();
new Thread(new TalkReceive(9999,"学生")).start();
}
}
创建学生线程
package Chat;
public class TalkStudent {
public static void main(String[] args) {
new Thread(new TalkSend(7777,"localhost",9999)).start();
new Thread(new TalkReceive(8888,"老师")).start();
}
}
URL下载网络资源
URL:统一资源定位符，定位互联网上的某个资源
DNS :域名解析 ,就是将www. baidu .com 解析为xx/xx/xx的ip
package Chat;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class UrlDemo {
public static void main(String[] args) throws Exception {
// 下载地址
URL url = new URL("http://m704.music.126.net/20220309111507/c4966ca9583be0e64ad7376c5e82af4c/jdyyaac/obj/w5rDlsOJwrLDjj7CmsOj/9018295932/59d4/5c86/b48e/c621d29448c519b580c3b25347bad8e8.m4a?authSecret=0000017f6c95721304db0aaba02d0ae6");
// 2.连接到资源 HTTP
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fos = new FileOutputStream("c.m4a"); //获取到文件
byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) != -1) {
fos.write(buffer, 0, len);
}
fos.close();
inputStream.close();
urlConnection.disconnect();// 断开连接
}
}
// System.out.println(url.getProtocol()); //协议
// System.out.println(url.getHost()); //主机ip
// System.out.println(url.getPort());// 端口
// System.out.println(url.getPath()); //文件
// System.out.println(url.getFile()); //全路径
// System.out.println(url.getQuery()); //参数
