我正在写一些代码和我不断收到这个错误,它与在那里我打电话network.addstation显示java.lang.NullPointerException在NetBeans
这里的代码,也有在网络中的其他方法做方法,但我想我只是显示一个,但它会出现在你调用任何方法时。任何帮助都会受到很大的帮助。谢谢。
public class MyNetworkReader implements NetworkReader {
Network network = null;
@Override
public Network read(InputStream stream) {
Scanner scan = null;
scan = new Scanner(stream);
while (scan.hasNext()) {
String fromStation = scan.next();
if (!fromStation.equalsIgnoreCase("connection:")) ;
network.addStation(fromStation)
System.out.println(fromStation);
}
}
return network;
}
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
public class MyNetwork implements Network {
HashMap<String, ArrayList> stations = new HashMap<String, ArrayList>();
public void addStation(String station) {
stations.put(station, null);
}
}