1：我们先去创建服务端Servier类

public class Server {
    public static void main(String[] args) {
        try {
            //给客户端一个接口让其连接
            ServerSocket serverSocket=new ServerSocket(8080);
            System.out.println("服务器启动完成...监听中");
            //开启监听 等待客户端的访问
           Socket socket= serverSocket.accept();
           //获取输入流，因为是客户端向服务器发送了数据
           InputStream inputStream= socket.getInputStream();
           //创建一个缓冲流
            BufferedReader br=new BufferedReader(new InputStreamReader(inputStream));
            String info=null;
            while ((info=br.readLine())!=null){
                System.out.println("这里是服务端 客户端说:"+info);
            }
               //向客户端做出响应
            OutputStream outputStream=socket.getOutputStream();
            info="这里是服务端我们接受到了你的消息";
            outputStream.write(info.getBytes());
            outputStream.flush();
            outputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

2:我们接下来去创建客户端Client类

public class Client {
    public static void main(String[] args) {
        try {

            Socket socket=new Socket("localhost",8080);
            OutputStream outputStream=socket.getOutputStream();
            String info="向服务端发送消息!";
            //输出!(输出流向服务器发送数据)
            outputStream.write(info.getBytes());
            socket.shutdownOutput();
            //接收服务端的响应
            InputStream inputStream1 = socket.getInputStream();
            BufferedReader br=new BufferedReader(new InputStreamReader(inputStream1));
            while ((info=br.readLine())!=null){
                System.out.println("接受到服务端的响应"+info);
            }
            //刷新缓冲区
            outputStream.flush();
            outputStream.close();
            inputStream1.close();
            socket.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

3:然后我们先去启动服务端，服务端显示启动,然后再去启动客户端，每运行一次客户端，服务端都会接收到一条消息!，并且回复客户端!