Map 嵌套map 遍历

最新推荐文章于 2023-11-17 18:50:09 发布

转载最新推荐文章于 2023-11-17 18:50:09 发布 · 1.1k 阅读

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原文链接：https://www.nuomiphp.com/eplan/412686.html

文章标签：

#java #map

该代码片段展示了如何将包含嵌套Map和List的结构扁平化为单一的Map。它通过迭代Map的每个条目，检查值是否是另一个Map或List，然后递归处理这些值，将键连接起来，并将结果存储在结果Map中。

private static Map<String, Object> flatten(final String key, final Map<String, Object> map,
        final Map<String, Object> result) {
    final Set<Map.Entry<String, Object>> entries = map.entrySet();
    if (!entries.isEmpty()) {
        for (final Map.Entry<String, Object> entry : entries) {
            //iterate over entries
            final String currKey = key + (key.isEmpty() ? "" : '.') + entry.getKey();
           //append current key to previous key, adding a dot if the previous key was not an empty String
            final Object value = entry.getValue();
            if (value instanceof Map) {//current value is a Map
                flatten(currKey, (Map<String, Object>) value, result);//flatten Map
            } else if (value instanceof List) {//current value is a List
                final List<Object> list = (List<Object>) value;
                for (int i = 0, size = list.size(); i < size; i++) {
                    result.put(currKey + '.' + (i + 1), list.get(i));
                }
                //iterate over the List and append the index to the current key when setting value
            } else {
                result.put(currKey, value);//set normal value
            }
        }
    }
    return result;
}