java广播问题

import java.io.*;
import java.net.*;
public class client {
 private static final int PORT = 9050;  
 private DatagramSocket dataSocket;  
 private DatagramPacket dataPacket;   
 private byte sendDataByte[];  
 private String sendStr;  
 public client() {      
  Init();   
  }   
 public void Init() {   
  try {          
   // 指定端口号，避免与其他应用程序发生冲突        
   dataSocket = new DatagramSocket(PORT); 
   sendDataByte = new byte[1024];
   sendStr = "READ"; 
   sendDataByte = sendStr.getBytes();
   dataPacket = new DatagramPacket(sendDataByte, sendDataByte.length,
     InetAddress.getByName("localhost"), PORT);
   dataSocket.send(dataPacket);
   } catch (SocketException se) {
    se.printStackTrace();
    } catch (IOException ie) {  
     ie.printStackTrace();        }
    }
  public static void main(String args[]) {   
  
   new client();
   }
 }

为什么没有发送出去？

你写接收程序了吗？？