Java Socket例程1

HelloServer.java

import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class HelloServer{
    public static void main(String args[]) throws IOException{
        ServerSocket serversocket = null;
        PrintWriter out = null;
        try{
            serversocket = new ServerSocket(9999);
        }
        catch(IOException e)
        {
            System.err.println("Could not listen on port:9999");
            System.exit(1);
        }
        
        Socket clientsocket = null;
        try{
            clientsocket = serversocket.accept();
        }
        catch(IOException e)
        {
            System.err.println("Accept failed.");
            System.exit(1);
        }
        out = new PrintWriter(clientsocket.getOutputStream(),true);
        out.println("hello world");
        clientsocket.close();
        serversocket.close();
    }
}

HelloClient.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;
import java.net.UnknownHostException;

public class HelloClient{
    public static void main(String args[]) throws IOException{
        Socket hellosocket = null;
        BufferedReader in = null;
        try{
            hellosocket = new Socket("localhost",9999);
            in = new BufferedReader(new InputStreamReader(hellosocket.getInputStream()));
        }
        catch(UnknownHostException e){
            System.err.println("Don't know about host:localhost");
            System.exit(1);
        }
        catch(IOException e)
        {
            System.err.println("Count't get I/O for the connection.");
            System.exit(1);
        }
        System.out.println(in.readLine());
        in.close();
        hellosocket.close();
    }
}

实现功能:先启动服务器,再启动客户端.连接成功之后,服务器给向客户端发送Hello World!