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[英]How to identify whether a received packet is using TCP or UDP, in java using jpcap?
[英]How to identify whether a received packet is IPPacket or ARPPacket in java using jpcap?
我正在捕獲IPPackets並使用Jpcap Library在Java中分析捕獲的數據包。但是捕獲的數據包是ARPPacket,我的程序顯示以下錯誤。
塊引用
線程“主”中的異常java.lang.ClassCastException:jpcap.packet.ARPPacket無法轉換為jpcap.packet.IPPacket。
塊引用
因此,如何確定接收到的數據包是IPPacket還是ARPPacket。 代碼的核心概念在這里:
import jpcap.*;
import jpcap.packet.IPPacket;
import jpcap.packet.Packet;
public class Capture {
public static void main(String[] args) throws IOException {
NetworkInterface[] device=JpcapCaptor.getDeviceList();
Packet packet;
JpcapCaptor captor=JpcapCaptor.openDevice(device[0], 65535, true, 20);
for(;;){
packet=captor.getPacket();
IPPacket p=(IPPacket)packet;
if(p!=null)
System.out.println("protocol id is"+p.protocol);
}
}
}
我該如何克服這個錯誤。謝謝。
檢查條件
if(packet instanceof ARPPacket) {
ARPPacket arp = (ARPPacket) packet;
// do somthing with ARPPacket
} else if(packet instanceof IPPacket) {
// do something with IP Packet
IPPacket arp = (IPPacket) packet;
}
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