如何获得两个映射Java之间的区别？ [英] How to get the difference between two maps Java?

问题描述

我有两张地图如下：

Map<String, Record> sourceRecords;
Map<String, Record> targetRecords;

我想获得每个maps.i.e的密钥不同。

I want to get the keys differ from each of the maps.i.e.

1. 它显示sourceRecords中可用的映射键，但不显示targetRecords中的映射键。


2. 它显示可用的映射键在targetRecords但不在sourceRecords中。

我这样做如下：

Set<String> sourceKeysList = new HashSet<String>(sourceRecords.keySet());
Set<String> targetKeysList = new HashSet<String>(targetRecords.keySet());

SetView<String> intersection = Sets.intersection(sourceKeysList, targetKeysList);
Iterator it = intersection.iterator();
while (it.hasNext()) {
    Object object = (Object) it.next();
    System.out.println(object.toString());
}

SetView<String> difference = Sets.symmetricDifference(sourceKeysList, targetKeysList);
ImmutableSet<String> immutableSet = difference.immutableCopy();

编辑

if(sourceKeysList.removeAll(targetKeysList)){
            //distinct sourceKeys
            Iterator<String> it1 = sourceKeysList.iterator();
            while (it1.hasNext()) {
                String id = (String) it1.next();
                String resultMessage = "This ID exists in source file but not in target file";
                System.out.println(resultMessage);
                values = createMessageRow(id, resultMessage);
                result.add(values);
            }
        }
        if(targetKeysList.removeAll(sourceKeysList)){
            //distinct targetKeys
            Iterator<String> it1 = targetKeysList.iterator();
            while (it1.hasNext()) {
                String id = (String) it1.next();
                String resultMessage = "This ID exists in target file but not in source file";
                System.out.println(resultMessage);
                values = createMessageRow(id, resultMessage);
                result.add(values);
            }
        }

我能找到公共密钥但不能区分键。请帮助。

I am able to find the common keys but not distinct keys. Please help.

推荐答案

设置允许您删除元素。

如果生成帮助集对你来说不是问题（因为条目太多;那么：

If generating "helper" sets is not a problem for you (because of too many entries; what about:

Set<String> sources = get a copy of all source entries
Set<String> targets = get a copy of all source entries

然后：

sources.removeAll(targets) ... leaves only entries in sources that are only in sources, not in target

而

sources.retainAll(targets) ... leaves only entries that are in both sets

你可以从这里开始工作......

You can work your way from here ...

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