使用Java merge对Map<String、Map<String、Integer>>中的数字求和

import java.util.HashMap;
import java.util.Map;

public class MapSumCalculator {
    public static void main(String[] args) {
        // 原始的Map<String, Map<String, Integer>>
        Map<String, Map<String, Integer>> originalMap = new HashMap<>();
        // 添加示例数据
        Map<String, Integer> innerMap1 = new HashMap<>();
        innerMap1.put("A", 10);
        innerMap1.put("B", 20);
        originalMap.put("Key1", innerMap1);

        Map<String, Integer> innerMap2 = new HashMap<>();
        innerMap2.put("C", 30);
        innerMap2.put("D", 40);
        originalMap.put("Key2", innerMap2);

        // 结果Map
        Map<String, Map<String, Integer>> resultMap = new HashMap<>();

        // 遍历原始Map，进行求和操作
        for (Map.Entry<String, Map<String, Integer>> entry : originalMap.entrySet()) {
            String outerKey = entry.getKey();
            Map<String, Integer> innerMap = entry.getValue();

            // 判断结果Map中是否已存在当前外层键
            if (!resultMap.containsKey(outerKey)) {
                // 若不存在，则将当前外层键和内层Map添加到结果Map中
                resultMap.put(outerKey, new HashMap<>(innerMap));
            } else {
                // 若存在，则进行合并操作
                Map<String, Integer> resultInnerMap = resultMap.get(outerKey);
                for (Map.Entry<String, Integer> innerEntry : innerMap.entrySet()) {
                    String innerKey = innerEntry.getKey();
                    int innerValue = innerEntry.getValue();

                    // 判断结果Map的内层Map中是否已存在当前键
                    if (!resultInnerMap.containsKey(innerKey)) {
                        // 若不存在，则直接将键和值添加到结果Map的内层Map中
                        resultInnerMap.put(innerKey, innerValue);
                    } else {
                        // 若存在，则将对应的值相加，并更新结果Map的内层Map中的值
                        int resultValue = resultInnerMap.get(innerKey) + innerValue;
                        resultInnerMap.put(innerKey, resultValue);
                    }
                }
            }
        }

        // 打印求和后的结果
        for (Map.Entry<String, Map<String, Integer>> entry : resultMap.entrySet()) {
            String outerKey = entry.getKey();
            Map<String, Integer> resultInnerMap = entry.getValue();

            System.out.println("Outer Key: " + outerKey);
            for (Map.Entry<String, Integer> innerEntry : resultInnerMap.entrySet()) {
                String innerKey = innerEntry.getKey();
                int resultValue = innerEntry.getValue();

                System.out.println("Inner Key: " + innerKey + ", Sum: " + resultValue);
            }
        }
    }
}