为什么我在下面的程序中得到UnsatisfiedLinkError？

Question

Error is :Exception in thread "main" java.lang.UnsatisfiedLinkError: 
    jpcap.JpcapCaptor.getDeviceList()[Ljpcap/NetworkInterface; at 
    jpcap.JpcapCaptor.getDeviceList(Native Method) at 
    jcap.network.main(network.java:63) 

---

import jpcap.*; 
import jpcap.packet.*; 
import java.io.*; 
import jpcap.packet.TCPPacket.*; 
import java.io.*; 
import jpcap.JpcapCaptor.*; 


class Network implements PacketReceiver { 
    System.out.println(System.getProperty("java.library.path")); 
    String sp=null; 
    String dp=null; 
    String window=null; 
    String sequence=null; 
    String acknowledge=null; 
    FileWriter ff=null; 
    String da=null; 

    public void receivePacket(Packet pt) { 
     try { 
      if(pt instanceof TCPPacket) { 
       TCPPacket tp=(TCPPacket)pt; 
       ff=new FileWriter("da.txt",true); 
       sp=new Integer(tp.src_port).toString(); 
       dp=new Integer(tp.dst_port).toString(); 
       window=new Integer(tp.window).toString(); 
       sequence=new Long(tp.sequence).toString(); 
       acknowledge=new Long(tp.ack_num).toString(); 
       byte[]dat=tp.data; 
       da=new String(dat); 
       ff.write("\r\n Source port is :-"+sp);  
       ff.write("\r\n Desination port is:-"+dp); 
       ff.write("\r\n Sequence no is:-"+sequence); 
       ff.write("\r\n Acknowledgement no is:-"+acknowledge); 
       ff.write("\r\n Status of rsv1 flag is:-"+tp.rsv1); 
       ff.write("\r\n Status of rsv2 flag is:-"+tp.rsv2); 
       ff.write("\r\n Status of Syn flag is:-"+tp.syn); 
       ff.write("\r\n Status of Urg flag is:-"+tp.urg); 
       ff.write("\r\n Status of Fin flag is:-"+tp.fin); 
       ff.write("\r\n Data :-"+da); 
       ff.write("\r\n"); 
       ff.write("\r\n"); 
       ff.close(); 
      }     
     } catch(Exception e) { 
      System.out.println(e.getMessage()); 
     } 
    } 

    public static void main(String args[])throws IOException { 
     int i;   
     try { 
      NetworkInterface[] devices = JpcapCaptor.getDeviceList(); 

      //for each network interface 
      for (i = 0; i < devices.length; i++) { 
       //print out its name and description 
       System.out.println(i+": "+devices[i].name + "(" +  
         devices[i].description+")"+devices[i].loopback); 
       //print out its datalink name and description 
       System.out.println(" datalink: "+devices[i].datalink_name + "(" 
         + devices[i].datalink_description+")"); 

       //print out its MAC address 
       System.out.print(" MAC address:"); 
       for (byte b : devices[i].mac_address) 
        System.out.print(Integer.toHexString(b&0xff) + ":"); 
       System.out.println(); 

       //print out its IP address, subnet mask and broadcast address 
       for (NetworkInterfaceAddress a : devices[i].addresses) 
        System.out.println(" address:"+a.address + " " + a.subnet + " "+ 
          a.broadcast); 
      } 
      JpcapCaptor captor=JpcapCaptor.openDevice(devices[0], 65535, true, 20); 
      captor.loopPacket(-1,new Network()); 
      captor.close(); 
     } 
     catch(Exception e) { 
      System.out.println(e.getMessage()); 
     } 
    } 
} 

Answer 1

为UnsatisfiedLinkError的javadoc是非常简单的。你缺少一些需要的jcap的lib。

将来，javadocs是一个很好的开始，当你遇到你不了解的异常时。

Answer 2

UnsatisfiedLinkError意味着，“JpcapCaptor”本地库没有被加载，

static{ 
     System.loadLibrary("JpcapCaptor.dll"); 
} 

Answer 3

在你的机器上安装JPCAP然后尝试运行代码。 您可以从这里下载jpcap.exe文件http://jpcap.software.informer.com/0.7/

Answer 4

我完全编译和链接Jpcap（在Mac OS X计算机上使用eclipse）后出现同样的问题。原来有两个版本的Jpcap：https://github.com/jpcap/jpcap（没有JpCaptor），和一个JpCaptor版本：https://github.com/mgodave/Jpcap。也许这有帮助。