如何通过键和值比较两个图并将差异图存储在结果图中 [英] How to compare two maps by both key and value and storing difference map in resultant map

问题描述

让我们说我有两张地图:

Lets say I have two maps:

Map mapA = new HashMap();
Map mapB = new HashMap();

mapA.put("JEETENDRA", "24");
mapA.put("AHUJA", "24"); --1A
mapA.put("AHUJA", "25");---2A
mapA.put("PAL", "24");

mapB.put("AHUJA", "24");
mapB.put("JEETENDRA", "24");---1B
mapB.put("PAL", "24");

现在我想通过键和值来比较两个映射，因为2A和1A具有通用的键.理想情况下，我知道它是错误的，因为键对于map应该是唯一的，但是在代码中，我正在检索两列记录并将其存储为map.

Now i want to compare both maps by both key and value since 2A and 1A have key common. I know ideally its wrong since key should be unique for map but in code I am retrieving two column record and storing it as map.

MapA在操作之前.
MapB经过一些操作.

MapA is before operations.
MapB is after some operations.

推荐答案

您可以使用此方法，在这里我使用了泛型，并且使用了一个TreeMap及其名称结果来保存此方法中两个HashMaps中的所有键.您将在Hashmaps中获得所有匹配的对象

you can use this method, here I have used the Generics, and I have used one TreeMap with name result to hold all keys inside both HashMaps , from this method you will get all the matched objects in Hashmaps

public static <K extends Comparable<? super K>, V>
    Map<K, Boolean> compareKeysAndValues(final Map<K, V> map1,
        final Map<K, V> map2){
        final Collection<K> allKeys = new HashSet<K>();
        allKeys.addAll(map1.keySet());
        allKeys.addAll(map2.keySet());
        final Map<K, Boolean> result = new TreeMap<K, Boolean>();
        for(final K key : allKeys){
            result.put(key,
                map1.containsKey(key) == map2.containsKey(key) &&
                Boolean.valueOf(equal(map1.get(key), map2.get(key))));
        }
        return result;
    }

如果要获取不同的值，只需将result.put函数中的check反转即可.

and if you want to get the value which are different simply reverse the check in result.put function

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