public class Service {public static void main(String[] args) {try {ServerSocket serverSocket = new ServerSocket(8888);Socket socket = serverSocket.accept();InputStream is = socket.getInputStream();InputStreamReader isr = new InputStreamReader(is);BufferedReader br = new BufferedReader(isr);String info = null;while((info = br.readLine())!=null){System.out.println("服务器，客户端请求："+info);}socket.shutdownInput();br.close();isr.close();is.close();socket.close();} catch (Exception e) {e.printStackTrace();}}
}

public class Client {public static void main(String[] args) {try {Socket socket = new Socket("localhost",8888);OutputStream os = socket.getOutputStream();PrintWriter pw = new PrintWriter(os);pw.write("用户名：admin;密码：admin");pw.flush();socket.shutdownOutput();pw.close();os.close();} catch (Exception e) {e.printStackTrace();}}
}

package org.socket.demo;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public class UDPService {public static void main(String[] args) {try {/*** 接收客户端发送过来的数据信息*///1.创建服务器端DataramSocket，指定端口号DatagramSocket datagramSocket = new DatagramSocket(8800);//2.创建数据报，用于接收客户端发送的数据byte[] data = new byte[1024];//创建字节数组，指定接收的数据包的大小DatagramPacket packet = new DatagramPacket(data,data.length);//3.接收客户端发送的数据datagramSocket.receive(packet);//此方法在接收到数据报之前会一直阻塞//读取数据String info = new String(data,0,packet.getLength());System.out.println("我是服务器，客户端说："+info);/*** 回应客户端的信息*/byte[] data2 = "欢迎您".getBytes();InetAddress inetAddress = packet.getAddress();int port = packet.getPort();DatagramPacket packet2 = new DatagramPacket(data2,data2.length,inetAddress,port);datagramSocket.send(packet2);datagramSocket.close();} catch (Exception e) {e.printStackTrace();}}
}

package org.socket.demo;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public class UDPClient {public static void main(String[] args) {//1.定义服务器的地址、端口号、数据try {/*** 向服务器端发送请求*/InetAddress address = InetAddress.getByName("localhost");int port = 8800;byte[] data = "用户名：admin;密码：123".getBytes();//2、创建数据报，包含发送的数据信息DatagramPacket packet = new DatagramPacket(data, data.length, address, port);//3、创建DatagramSocket对象DatagramSocket socket = new DatagramSocket();socket.send(packet);/*** 接收服务器端发送过来的数据信息*/byte[] data2 = new byte[1024];//创建字节数组，指定接收的数据包的大小DatagramPacket packet2 = new DatagramPacket(data2,data2.length);//3.接收客户端发送的数据socket.receive(packet2);//此方法在接收到数据报之前会一直阻塞String info = new String(data2,0,packet2.getLength());System.out.println("我是客户端，服务器说："+info);socket.close();} catch (Exception e) {e.printStackTrace();}}
}

ObjectOUTputStream, writeObject()---->传输的对象必须实现序列化接口，implements Serializable，否则报异常
Socket socket = new Socket("localhost",8888);
OutputStream os = socket.getOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(os);
User user = new User("amdin","123");
oos.writeObject(user);
socket.shutdownOutput();

ObjectInputStream,readObject()
InputStream is = socket.getInputStream();
ObjectInputStream ois = new ObjectInputStream(is);
User user = (User)ois.readObject();
System.out.println(user.getUsername()+"\t"+user.getPassword());
socket.shutdownInput();