import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.net.ServerSocket;

import java.net.Socket;

public class HelloWorldServer {

    public static void main(String[] args) {

        ServerSocket server = null;

        BufferedReader reader = null;

        Socket client = null;

        try {

            server = new ServerSocket();//创建ServerSocket对象，并绑定端口

            client = server.accept();//调用accept方法，等待客户端的连接

            InputStream in = client.getInputStream();

            reader = new BufferedReader(new InputStreamReader(in));

            String str = reader.readLine();

            System.out.println(str);

        } catch (IOException e) {

            e.printStackTrace();

        }finally{

            try{

                if(client!=null){

                    client.close();

                }

            }catch(IOException e){

                e.printStackTrace();

            }

        }

    }

}

import java.io.IOException;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.Socket;

import java.net.UnknownHostException;

import java.util.Scanner;

public class HelloWorldClient {

    public static void main(String[] args) {

        Socket client = null;

        PrintWriter writer = null;

        try {

            client = new Socket("www.feifeishi.cn", );//www.feifeishi.cn是我的云服务器

            OutputStream out = client.getOutputStream();

            writer = new PrintWriter(out);

            Scanner sc=new Scanner(System.in);

            String aa=sc.nextLine();

            writer.print(aa);

            writer.flush();

        } catch (UnknownHostException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }finally{

            try{

                if(writer!=null){

                    writer.close();

                }

                if(client!=null){

                    client.close();

                }

            }catch(IOException e){

                e.printStackTrace();

            }

        }

    }

}