在Java ConcurrentHashMap中打印所有键/值对 [英] Print all key/value pairs in a Java ConcurrentHashMap

问题描述

我试图在ConcurrentHashMap中打印所有的键/值对。

我在网上发现了这个代码，我认为它会这样做，但它似乎获取有关桶/散列码的信息。其实老实说输出它很奇怪，它可能我的程序是不正确的，但我首先要确定这部分是我想要使用的。

<$ p $ （Entry< StringBuilder，Integer> entry：wordCountMap.entrySet（））{
String key = entry.getKey（）。toString（）;
整数值= entry.getValue（）;
System.out.println（key，+ key +value+ value）;



$ b $ p
$ b

这给出了大约10个不同键的输出，计数似乎是总和插入到地图中的总数。

解决方案

我测试了你的代码并正常工作。我添加了一个小样本，以另一种方式打印地图中的所有数据：

  ConcurrentHashMap< String，Integer> map = new ConcurrentHashMap< String，Integer>（）; 
 map.put（A，1）; 
 map.put（B，2）; 
 map.put（C，3）; （String key：map.keySet（））{
 System.out.println（key ++ map.get（key））; 
 
 （Map.Entry< String，Integer> entry：map.entrySet（））{
 String key = entry.getKey（）。toString（）; 
 
 
 
整数值= entry.getValue（）; 
 System.out.println（key，+ key +value+ value）; 
} 
  

I am trying to simply print all key/value pair(s) in a ConcurrentHashMap.

I found this code online that I thought would do it, but it seems to be getting information about the buckets/hashcode. Actually to be honest the output it quite strange, its possible my program is incorrect, but I first want to make sure this part is what I want to be using.

for (Entry<StringBuilder, Integer> entry : wordCountMap.entrySet()) {
    String key = entry.getKey().toString();
    Integer value = entry.getValue();
    System.out.println("key, " + key + " value " + value);
}

This gives output for about 10 different keys, with counts that seem to be the sum of the number of total inserts into the map.

解决方案

I tested your code and works properly. I've added a small demo with another way to print all the data in the map:

ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<String, Integer>();
map.put("A", 1);
map.put("B", 2);
map.put("C", 3);

for (String key : map.keySet()) {
    System.out.println(key + " " + map.get(key));
}

for (Map.Entry<String, Integer> entry : map.entrySet()) {
    String key = entry.getKey().toString();
    Integer value = entry.getValue();
    System.out.println("key, " + key + " value " + value);
}

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