Java网络编程03：UDP
Java网络编程03：UDP
发短信：不用连接，需要知道对方的地址！
UDP消息发送
发送端
//不需要连接服务器
public class UdpClientDemo01 {
public static void main(String[] args) throws Exception {
//1.建立一个Socket
DatagramSocket socket = new DatagramSocket();
//2.建个包
String msg = "你好，服务器";
InetAddress localhost = InetAddress.getByName("localhost");
int port = 9090;
//数据，数据的长度起始，发送给谁
DatagramPacket packet = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);
//3发送包
socket .send(packet);
//4.关闭流
socket.close();
}
}
接收端
//还是要等待客户端的连接！
public class UdpServerDemo01 {
public static void main(String[] args) throws Exception {
//开放端口
DatagramSocket socket = new DatagramSocket(9090);
//接收数据包
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();
}
}
循环发送消息
public class UdpSenderDemo01 {
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("bye")){
break;
}
}
socket.close();
}
}
public class UdpReceiveDemo01 {
public static void main(String[] args) throws Exception {
DatagramSocket socket = new DatagramSocket(6666);
while (true){
//准备接收包裹
byte[] container = new byte[1024];
DatagramPacket packet = new DatagramPacket(container,0,container.length);
socket.receive(packet);//阻塞式接收包裹
//断开连接 bye
byte[] data = packet.getData();
String receiveData = new String(data,0,data.length);
System.out.println(receiveData);
if (receiveData.equals("bye")){
break;
}
}
socket.close();
}
}
聊天室案例：
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);
reader = new BufferedReader(new InputStreamReader(System.in));
}catch (Exception e){
}
}
@Override
public void run() {
while (true){
try {
String 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("bye")){
break;
}
} catch (Exception e) {
e.printStackTrace();
}
}
socket.close();
}
}
public class TalkReceive implements Runnable {
DatagramSocket socket = null;
private int port;
private String msgFrom;
public TalkReceive(int port,String msgFrom){
this.port = port;
this.msgFrom = msgFrom;
try {
socket = new DatagramSocket(port);
}catch (Exception e){
}
}
@Override
public void run() {
while (true){
try {
//准备接收包裹
byte[] container = new byte[1024];
DatagramPacket packet = new DatagramPacket(container,0,container.length);
socket.receive(packet);//阻塞式接收包裹
//断开连接 bye
byte[] data = packet.getData();
String receiveData = new String(data,0,data.length);
System.out.println(msgFrom+"："+receiveData);
if (receiveData.equals("bye")){
break;
}
}catch (Exception e){
e.printStackTrace();
}
}
socket.close();
}
}
public class TalkStudent {
public static void main(String[] args) {
//开启两个线程
new Thread(new TalkSend(7777,"localhost",9999)).start();
new Thread(new TalkReceive(8888,"老师")).start();
}
}
public class TalkTeacher {
public static void main(String[] args) {
//开启两个线程
new Thread(new TalkSend(5555,"localhost",8888)).start();
new Thread(new TalkReceive(9999,"学生")).start();
}
}
URL
public class URLDemo01 {
public static void main(String[] args) throws MalformedURLException {
URL url = new URL("http://localhost:8080/helloword/index.jsp?username=zhangsan&password=123");
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
}
}
文件下载
public class UrlDown {
public static void main(String[] args) throws Exception {
//1.下载地址
URL url = new URL("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1595394077&di=d5136d84fb7c4265752c19242428233b&imgtype=jpg&er=1&src=http%3A%2F%2Fattach.bbs.miui.com%2Fforum%2F201111%2F21%2F205700txzuacubbcy91u99.jpg");
//2.连接到这个资源 HTTP
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fos = new FileOutputStream("9.jpg");
byte[] buffer = new byte[1024];
int len;
while ((len=inputStream.read(buffer))!=-1){
fos.write(buffer,0,len);//写出这个数据
}
fos.close();
inputStream.close();
urlConnection.disconnect();//断开连接
}
}