將兩個枚舉值存儲在HashMap中

Question

我想將socket.getSocket()和socketStatus.getSocketStatus()存儲在HashMap中。但hMap.put(socket.getSocket(),socketStatus.getSocketStatus());會拋出一個NullPointerException。我該如何解決這個問題？

下面是我的兩個類：

SocketInfoMap.java

package vd.socket.map; 

import java.util.HashMap; 
import java.util.Map; 

public class SocketInfoMap { 

    public enum Socket { 

     ONE("01"), TWO("02"), THREE("03"), FOUR("04"), FIVE("05"), SIX("06"), SEVEN("07"), EIGHT("08"); 

     private static Map<Socket, String> sMap = new HashMap<Socket, String>(); 
     private String socket; 

     private Socket(String socket) { 
      this.socket = socket; 
     } 

     public String getSocket() { 
      return socket; 
     } 

     static { 
      for (Socket socket : Socket.values()) { 
       sMap.put(socket, socket.getSocket()); 
      } 

     } 
    } 

    public enum SocketStatus { 

     LIFTED(1), NOT_LIFTED(0); 

     private static Map<SocketStatus, Integer> stMap = new HashMap<SocketStatus, Integer>(); 
     private int socketStatus; 

     private SocketStatus(int socketStatus) { 
      this.socketStatus = socketStatus; 
     } 

     public int getSocketStatus() { 
      return socketStatus; 
     } 

     static { 
      for (SocketStatus socketStatus : SocketStatus.values()) { 
       stMap.put(socketStatus, socketStatus.getSocketStatus()); 
      } 

     } 
    } 

    private static Map<String, Integer> hMap = new HashMap<String, Integer>(); 

    public SocketInfoMap(Map<String, Integer> hMap) { 
     SocketInfoMap.hMap = hMap; 
    } 

    public Map<String, Integer> gethMap() { 
     return hMap; 
    } 

} 

SocketMapTest.java

package vd.socket.map; 

import java.util.Map; 
import vd.socket.map.SocketInfoMap.*; 

public class SocketMapTest { 
    private static Map<String, Integer> hMap; 

    public static void main(String[] args) { 

     SocketStatus socketStatus = SocketStatus.LIFTED; 
     Socket socket = Socket.TWO; 

     if ((socket == Socket.TWO) && (socketStatus == SocketStatus.LIFTED)) { 
      hMap.put(socket.getSocket(), socketStatus.getSocketStatus()); 
      System.out.println(hMap); 
     } else 
      hMap.put(socket.getSocket(), socketStatus.getSocketStatus()); 
     System.out.println(hMap); 

    } 
} 

Answer 1

初始化HMAP主要方法裏面.. 通過這個鏈接，希望它會幫助你..

How do I store Enum types into a map?