第N+1个hello world-java socket

import java.io.*;
import java.net.*;
import java.util.Scanner;
public class ClientTest {
 public static void main(String args[]) throws IOException
        {
        InetAddress addr=InetAddress.getByName(null);
        System.out.println("addr="+addr);
        Socket socket=new Socket(addr,ServerTest.PORT);
        Scanner sc1 = new Scanner(System.in);
         String js=sc1.nextLine();
         System.out.println(js);   //打印输入内容
        try{
            System.out.println("socket="+socket);   //发送的情况
            BufferedReader in =new BufferedReader(new InputStreamReader(socket.getInputStream() ) );//这行不太懂
            PrintWriter out=new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream() ) ),true );

                out.println(js);//走

            out.println("END");
            }finally{
                System.out.println("closing...");
                socket.close();
            }
        }
}

import java.io.*;
import java.net.*;
public class ServerTest {

        public static final int PORT =8080;
        public static void main(String args[]) throws IOException{
            ServerSocket s=new ServerSocket(PORT);
            System.out.println("started:"+s);
            try{
                Socket socket=s.accept();   //监听数据
                try{
                    System.out.println("Connection accepted:"+socket);
                    BufferedReader in =new BufferedReader(new InputStreamReader(socket.getInputStream() ) );
                    PrintWriter out=new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()) ),true);
                    while(true)
                        {
                        String str=in.readLine();//来.
                        if(str.equals("END") )break;   //收到END就结束监听
                        System.out.println("Echoing:"+str);
                        out.println(str);//回
                        }
                    }finally{
                        System.out.println("closing");
                        socket.close();
                    }


            }finally{
                s.close();
            }
        }

    }
分别运行客户端和服务端.输入hello world 搞定.