import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;public class BasicSocketServer {public static void main(String[] args) {Socket socket = null;BufferedWriter bw = null;try {//1.简历服务器端套接字：指定监听的接口ServerSocket serverSocket = new ServerSocket(9999);System.out.println("服务器建立监听");//2.监听：等待客户端请求，并建立连接socket = serverSocket.accept();//3.获取Socket的输出流bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));//4.向客户端发送反馈信息bw.write("连接成功");//5.关闭流及socket连接} catch (IOException e) {e.printStackTrace();}finally {try {if(bw != null)bw.close();if(socket != null)socket.close();} catch (IOException e) {e.printStackTrace();}}               }
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;public class BasicSocketClient {public static void main(String[] args) {Socket socket = null;BufferedReader br = null;try {/** 创建Socket对象：指定要连接的服务器IP及端口号* 注意不是自己机器的端口，发送端口是随机的*/socket = new Socket(InetAddress.getLocalHost(), 9999);//获取Socket的输入流，并使用缓冲流进行包装br = new BufferedReader(new InputStreamReader(socket.getInputStream()));//接收服务端发送的信息System.out.println(br.readLine());} catch (UnknownHostException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}finally {try {//关闭流及Socket连接if(br != null)br.close();if(socket != null)socket.close();} catch (IOException e) {e.printStackTrace();}} }
}