2015-02-07 44 views
0

我正在模擬與Java網絡模擬器(JNS)的網絡拓撲。我遵循了JNS下載文檔中的教程。以下是示例代碼:Java網絡模擬器入門

package simulator_; 
import java.awt.peer.TextComponentPeer; 
import java.io.IOException; 

import jns.Simulator; 
import jns.element.DuplexInterface; 
import jns.element.DuplexLink; 
import jns.element.Interface; 
import jns.element.Link; 
import jns.element.Node; 
import jns.trace.Event; 
import jns.trace.Trace; 
import jns.util.IPAddr; 

public class simu { 

    public static void main(String[] args) { 
     Simulator sim=Simulator.getInstance(); 

     Node src=new Node("Source node"); 
     Node router=new Node("Router"); 
     Node dest=new Node("Destination node"); 
     sim.attach(src); 
     sim.attach(router); 
     sim.attach(dest); 


     Interface src_iface=new DuplexInterface(new IPAddr(192,168,1,10)); 
     src.attach(src_iface); 
     sim.attach(src_iface); 

     Interface dest_iface=new DuplexInterface(new IPAddr(128,116,11,20)); 
     dest.attach(dest_iface); 
     sim.attach(dest_iface); 


     Interface route_iface192=new DuplexInterface(new IPAddr(192,168,1,1)); 
     Interface route_iface128=new DuplexInterface(new IPAddr(128,116,11,1)); 

     router.attach(route_iface192); 
     router.attach(route_iface128); 

     sim.attach(route_iface192); 
     sim.attach(route_iface128); 


     Link link_src_router=new DuplexLink(1000000,0.001); 
     Link link_router_dest=new DuplexLink(64000,0.1); 

     src_iface.attach(link_src_router,true); 
     route_iface192.attach(link_src_router,true); 
     sim.attach(link_src_router); 

     route_iface128.attach(link_router_dest,true); 
     dest_iface.attach(link_router_dest,true); 
     sim.attach(link_router_dest); 


     src.addDefaultRoute(src_iface); 
     dest.addDefaultRoute(dest_iface); 

     router.addRoute(new IPAddr(192,168,1,0),new IPAddr(255,255,255,0), 
         route_iface192); 
     router.addRoute(new IPAddr(128,116,11,0),new IPAddr(255,255,255,0), 
         route_iface128); 

     sim.run(); 


    } 

} 

我面臨的問題是,當我打電話sim.run(),該程序引發NullPointerException異常我的錯誤。我是JNS的新手。請指導,如果我怎樣才能成功地創建一個文件與javis模擬與上述代碼的幫助。我正在使用Eclipse IDE。 在此先感謝。

+0

查看NullPointerException的堆棧跟蹤。你的代碼中哪行出現在堆棧跟蹤中? – 2015-02-28 20:00:56

回答

1

嘗試設置一個跟蹤實例

sim.setTrace(新JavisTrace( 「output.txt中」));