看不到HashMap的内容

看不到HashMap的内容

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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);
}
}


}



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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08-01 23:39