//文件名：ChatClient.java
import java.net.*;
import java.io.*;
/**
 * <p>Title: 網絡聊天吧</p>
 * <p>Description: 這是一個使用數據報通訊方式的聊天程序的客戶端</p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Filename: ChatClient.java</p>
 * @author 杜江
 * @version 1.0
 */
public class ChatClient{
 private DatagramSocket s;
 private InetAddress hostAddress;
 private byte[] buf = new byte[1000];
 private DatagramPacket dp = new DatagramPacket(buf,buf.length);

/**
 *<br>方法說明：構造器，這里實現接收用戶輸入和與服務器通訊
 *<br>輸入參數：
 *<br>返回類型：
 */
  public ChatClient(){
   try{
       //使用構造器，創建使用本機任何可用端口的數據包Socket
       s = new DatagramSocket();
       //獲取本地IP
       hostAddress = InetAddress.getByName("localhost");
       System.out.println("Client start............");
       while(true){
         String outMessage ="";  
        //讀取輸入
         BufferedReader stdin  = new BufferedReader(new InputStreamReader(System.in));
         try{
           outMessage = stdin.readLine();
         }catch(IOException ie){
           System.err.println("IO error!");
         }
         //如果輸入“bye”則表示退出程序
         if(outMessage.equals("bye")) break;
         String outString = "Client say: "+ outMessage;
         byte[] buf = outString.getBytes();
         //打包數據，發送數據
         DatagramPacket out = new DatagramPacket(buf,buf.length,hostAddress,ChatServer.PORT);
         s.send(out);
         //等待服務器返回
         s.receive(dp);
         String rcvd = "rcvd from "+ dp.getAddress() + ", " + dp.getPort() + 
         ": "+ new String(dp.getData(),0,dp.getLength());
         System.out.println(rcvd);
         
      }
     }catch(UnknownHostException e){
       System.out.println("Can;t open socket");
       System.exit(1);
     }catch(SocketException e){
       System.out.println("Can;t open socket");
       e.printStackTrace();
       System.exit(1);
     }catch(IOException e){
       System.err.println("Communication error");
       e.printStackTrace();
       System.exit(1);
     }catch(Exception e){
       System.err.println("Communication error");
       e.printStackTrace();
       System.exit(1);
     }
     System.out.println("ChatClient over");
 }
/**
 *<br>方法說明：主方法
 *<br>輸入參數：
 *<br>返回類型：
 */
 public static void main(String[] args){
    new ChatClient();
 }
}