看不到HashMap的内容 [英] Can't see the contents of the HashMap

问题描述

输出到达flag2，但我看不到HashMap内部的内容。代码如下：

  public class traffic_analysis {
 
 
 static HashMap< InetAddress，Integer> ; mp = new HashMap< InetAddress，Integer>（）; 
 
 
 static void SrcCnt（InetAddress src_ip）{
 InetAddress SourceIP = src_ip; 
 System.out.println（SourceIP）; 
 
 if（mp.get（SourceIP）== null）{
 mp.put（SourceIP，0）; 
 System.out.println（---- MPIKE ----）; 
} else {
 mp.put（SourceIP，mp.get（SourceIP）+1）; 
 System.out.println（---- MPIKE XANA ----）; 
} 
 
 System.out.println（mp.toString（））; 
 
 
 
 static void PrintMap（）{
 System.out.println（---- EIMAI EDW ----）; 
 
 Iterator iterator = mp.keySet（）。iterator（）; 
 
 while（iterator.hasNext（））{
 System.out.println（---- flag ----）; 
 String key = iterator.next（）。toString（）; 
 System.out.println（---- flag2 ----）; 
 String value = mp.get（key）.toString（）; 
 System.out.println（---- ---- flag3 ----）; 
 
 System.out.println（key +blabla+ value）; 
} 
} 
 
 
} 
  

<问题出在哪里？

字符串获取它时，将会失败。试试这个：

  InetAddress key = iterator.next（）; 
 System.out.println（---- flag2 ----）; 
 String value = mp.get（key）.toString（）; 
 System.out.println（---- ---- flag3 ----）; 
  

Output reaches flag2 but I can't see what is inside the HashMap. The code is:

public class traffic_analysis {


static HashMap<InetAddress,Integer> mp=new HashMap<InetAddress, Integer>();


    static void SrcCnt(InetAddress src_ip) {
        InetAddress SourceIP = src_ip;
        System.out.println(SourceIP);

        if (mp.get(SourceIP) == null){
            mp.put(SourceIP, 0);
            System.out.println("----MPIKE----");
        }else {
            mp.put(SourceIP,mp.get(SourceIP)+1);
            System.out.println("----MPIKE XANA----");
        }

        System.out.println(mp.toString());
    }


static void PrintMap() {
    System.out.println("----EIMAI EDW----");

    Iterator iterator = mp.keySet().iterator();

    while (iterator.hasNext()) {
         System.out.println("----flag----");
       String key = iterator.next().toString();
       System.out.println("----flag2----");
       String value = mp.get(key).toString();
       System.out.println("----flag3----");

       System.out.println(key + "blabla " + value);
    }
}


}

Where is the problem?

解决方案

You're calling toString on the actual key. When you try to get it with the string, that will fail. Try this instead:

InetAddress key = iterator.next();
System.out.println("----flag2----");
String value = mp.get(key).toString();
System.out.println("----flag3----");

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