servercom.java

实现多机的局域网聊天功能

import java.io.*;
import jpcap.*;				//引用jpcap包
import jpcap.NetworkInterface;
import jpcap.packet.*;
import java.util.*;	
import java.net.*;

class servercom  implements PacketReceiver
{
	
	public final static int port=5230;
	IPPacket ip;

public  void receivePacket(Packet packet)
{
	if(packet instanceof IPPacket)
	{
		int count=1;
        if(count%10==0)
        		System.out.println("第"+count+"次抓包成功！");
        		count++;
        		ip=(IPPacket)packet;
        		System.out.print(ip.src_ip+"\t\t"+ip.dst_ip+"\t"+ip.protocol+"\t"+
                ip.length+"\t"+ip.version+"\t\t"+ip.ident+"\t\t"+
                ip.rsv_frag+"\t\t"+ip.offset+"\t\t"+ip.hop_limit+"\t\t"+
                ip.rsv_tos+"\r\n");
        	try{
      	        RandomAccessFile rf = new RandomAccessFile("packet.txt", "rw");
                rf.seek(rf.length());
                rf.writeBytes(ip.src_ip+"\t"+ip.dst_ip+"\t"+ip.protocol+"\t"+
                ip.length+"\t"+ip.version+"\t"+ip.ident+"\t"+
                ip.rsv_frag+"\t"+ip.offset+"\t"+ip.hop_limit+"\t"+
                ip.rsv_tos+"\r\n");	/*向txt文件写入IP的源地址,目标地址,高层协议,长度, 版本号,标识符(序号),标志,段偏移量,数据报的寿命数值,服务型号,数据*/
                rf.close();
      			}
           catch (Exception e) 
           {e.printStackTrace();}
	}
}
public static void main(String args[])throws java.io.IOException
{
		String str;
		NetworkInterface[] devices =  JpcapCaptor.getDeviceList();
  	  	NetworkInterface deviceName = devices[0];
        JpcapCaptor jpcap1 =  JpcapCaptor.openDevice(deviceName, 1028, true, 1000);
        jpcap1.loopPacket(1000, new servercom());
        //即将打开的设备名
          //从设备上一次读取的最大字节数
          //说明是否将设备设为混杂模式的Boolean值
          //超时值
		try{
			ServerSocket server=new ServerSocket(port);
			System.out.println("本地电脑连接信息:"+server);
			Socket socket=server.accept();
			System.out.println("Socket状态:"+socket);
			InputStream fln=socket.getInputStream();
			OutputStream fout=socket.getOutputStream();
			InputStreamReader isr=new InputStreamReader(fln);
			BufferedReader in=new BufferedReader(isr);
			PrintStream out=new PrintStream(fout);
			InputStreamReader userisr=new InputStreamReader(System.in);
			BufferedReader userin=new BufferedReader(userisr);
			while(true)
			{
				System.out.println("等待客户机");
				str=in.readLine();
				System.out.println("客户端的消息:"+str);
				if(str.equals("#"))break; //#为退出标志
				System.out.println("请选择客户端要进行的操作：");
				System.out.println("1、进行抓包 2、让客户端退出");
				str=userin.readLine();
				out.println(str);
				if(str.equals("2"))break; //#为退出标志
			}
			socket.close();server.close();
		}	
		catch(Exception e)
			{System.out.println("异常来自"+e);}
	}
}