server.java

用udp实现可靠数据传递

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;


public class Server {
	private static int number=0;
 
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		byte[] by = new byte[1024];
        String s  ;
        String s1;
        String s2;
        DatagramSocket ds = new DatagramSocket(9000);
        DatagramPacket dp = new DatagramPacket(by,by.length);
        DatagramPacket dp1 =null;
        FileWriter fw =new FileWriter("f:/ss/ss1.txt");
        BufferedWriter bw = new BufferedWriter(fw);
        while(true){
        	 ds.receive(dp);
             ++number;
             s = new String(dp.getData(),0,dp.getLength());
             s1 = s.substring(1);
             s2 = s.substring(0,1);
             Integer	it = new Integer(s2);
     		int i = it.intValue();
     		System.out.println(s1);
     		s2 = s.substring(0,1);
     		System.out.println(number);
             if(number==i){
             	 bw.write(s1);
                  bw.newLine();
                  bw.flush();
             }else{
            	 number--;
             }
             System.out.println(number);
             by = s2.getBytes();
             dp1 = new DatagramPacket(by,by.length,new InetSocketAddress("127.0.0.1",8888));
             ds.send(dp1);
        }
       
	}

}