用java写一个可以发送和接收得socket客户端和服务端例子

好的，以下是一个简单的Java Socket客户端和服务端的例子：

服务端代码：

import java.io.*;
import java.net.*;

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;
        try {
            serverSocket = new ServerSocket(8080); // 监听8080端口
        } catch (IOException e) {
            System.err.println("Could not listen on port: 8080.");
            System.exit(1);
        }

        Socket clientSocket = null;
        try {
            System.out.println("Waiting for connection...");
            clientSocket = serverSocket.accept(); // 等待客户端连接
            System.out.println("Connected to client: " + clientSocket.getInetAddress().getHostName());
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        String inputLine;
        while ((inputLine = in.readLine()) != null) {
            System.out.println("Received from client: " + inputLine);
            out.println("Server received: " + inputLine); // 发送回复给客户端
        }

        out.close();
        in.close();
        clientSocket.close();
        serverSocket.close();
    }
}

客户端代码：

import java.io.*;
import java.net.*;

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = null;
        PrintWriter out = null;
        BufferedReader in = null;

        try {
            socket = new Socket("localhost", 8080); // 连接到本地8080端口
            out = new PrintWriter(socket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host: localhost.");
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to: localhost.");
            System.exit(1);
        }

        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        String userInput;
        while ((userInput = stdIn.readLine()) != null) {
            out.println(userInput); // 发送消息给服务器
            System.out.println("Received from server: " + in.readLine()); // 接收服务器的回复
        }

        out.close();
        in.close();
        stdIn.close();
        socket.close();
    }
}

这个例子中，服务端监听8080端口，等待客户端连接。一旦客户端连接上来，服务端会接收客户端发送的消息，并将收到的消息回复给客户端。客户端连接到本地的8080端口，向服务端发送消息，并接收服务端的回复。