简单互动:

服务器:

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

public class TCPServer {
    public static void main(String[] args) {
        ServerSocket serverSocket = null;
        BufferedReader bufferedReader = null;
        try {
            //创建服务器套接字,并指明监听接口
            serverSocket = new ServerSocket(6688);
            System.out.println("服务器启动!!!");
            //.accept(字面意思为接收):接收一个套接字中已建立的连接
            Socket socket = serverSocket.accept();
            //.getHostAddress()(字面意思即为获取主机地址)
            System.out.println("有客户端请求连接，ip："+ socket.getInetAddress().getHostAddress());
            //BufferedReader:(缓冲读写对象)从字符输入流中读取文本，缓冲各个字符，从而实现字符、数组和行的高效读取。
            //InputStreamReader(输入流读写对象)getInputStream(获取输入流)
            bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            //readLine:读取流读数据
            System.out.println("输出客户端信息：" + bufferedReader.readLine());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedReader != null) {
                    bufferedReader.close();
                }
                if (serverSocket != null) {
                    serverSocket.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

客户端

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;

public class TCPClient {
    public static void main(String[] args) {
        Socket socket = null;
        BufferedWriter bufferedWriter = null;
            //根据ip地址和端口号进行连接
            try {
                socket = new Socket("127.0.0.1", 6688);
                System.out.println("与服务器端建立连接...");
                System.out.println("客户端输入信息：");
                Scanner sc = new Scanner(System.in);
                //bufferedWriter:缓冲输出流
                bufferedWriter = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
                //把输入字符串注入缓冲输出流(bufferedWriter)
                bufferedWriter.write(sc.nextLine());
                bufferedWriter.flush();
            } catch (UnknownHostException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                try {
                    if (bufferedWriter != null) {
                        bufferedWriter.close();
                    }
                    if (socket != null) {
                        socket.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
    }
}