1、TCP Socket编程实现服务器和客户端的交互： （1）服务器端先运行，利用循环时刻为客户端提供服务； （2）客户端与服务器接通后，从键盘上输入若干字符（若客户端发送“end”字符串，服务器终止程序），传到服务器，服务器在控制台显示所收到的数据，形式为：”I have received ******”，并向客户端 反馈信息“Message from Server is:******”，此次通话结束； （3）客户端接收来自服务器端的数据，在控制台显示：“Client has received .............“。

下面是TCP Socket实现服务器和客户端交互的代码：

服务器端代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8888);
        System.out.println("Server is listening on port 8888...");

        while (true) {
            Socket clientSocket = serverSocket.accept();
            System.out.println("Accepted connection from client " + clientSocket.getInetAddress() + ":" + clientSocket.getPort());

            BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);

            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                System.out.println("Received message from client: " + inputLine);
                if ("end".equals(inputLine)) {
                    break;
                }
                out.println("Message from Server is: " + inputLine);
                System.out.println("Sent message to client: " + inputLine);
            }

            in.close();
            out.close();
            clientSocket.close();
            System.out.println("Connection with client closed.");
        }
    }
}

客户端代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class Client {

    public static void main(String[] args) throws IOException {
        String hostName = "localhost";
        int portNumber = 8888;

        try (Socket socket = new Socket(hostName, portNumber);
             PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
             BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
             BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in))) {

            String userInput;
            while ((userInput = stdIn.readLine()) != null) {
                out.println(userInput);
                if ("end".equals(userInput)) {
                    break;
                }
                System.out.println("Client has sent message: " + userInput);

                String serverResponse = in.readLine();
                System.out.println("Server response: " + serverResponse);
            }
        } catch (IOException e) {
            System.err.println("Could not connect to " + hostName + ":" + portNumber);
            System.exit(1);
        }
    }
}

在客户端中，用户输入的信息通过PrintWriter的println方法发送给服务器端；服务器端收到信息后，在控制台显示，并通过PrintWriter的println方法向客户端反馈信息；客户端收到服务器端的信息后，在控制台显示。当用户输入"end"时，程序结束。