端口连接Socket.异常时写入文件

import java.net.*;
import java.io.*;
class Demo5 
{
public static void main(String[] args) throws Exception
{
Fun f=new Fun();
Thread t=new Thread(f);
t.start();
DatagramSocket socket=new DatagramSocket();
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
String line=null;
while((line=br.readLine())!=null)
{
if("over".equals(line))
break;
byte[] data=line.getBytes(); 
DatagramPacket packet=new DatagramPacket(data,data.length,InetAddress.getByName("10.0.185.14"),10000);
socket.send(packet);
}


socket.close();

}
}
class Fun implements Runnable
{
File f=new File("t.txt");
PrintWriter fw=null;
public void run()
{
try
{
fw=new PrintWriter(f);
DatagramSocket socket=new DatagramSocket(1000000);
while(true)
{
byte[] arr=new byte[1024];
DatagramPacket packet=new DatagramPacket(arr,arr.length);
socket.receive(packet);
String content=new String(packet.getData(),0,packet.getLength());
String ip=packet.getAddress().getHostAddress();
int port=packet.getPort();
System.out.println(ip+","+port+","+content);
}
}
catch (Exception e) 
{
e.printStackTrace(fw);
System.out.println("程序异常，无法与对面进行连接");
}
fw.close();
}
}