Java 代码优化: 使用流和函数式编程转换多级 Map

public static <T, V> Map<String, Map<String, V>> convertMultistageMapByFunction( final Map<String, Map<String, T>> computeResultNameGroup, final Function<? super Map.Entry<String, T>, ? extends V> valueMapper) { return MapUtils.emptyIfNull(computeResultNameGroup) .entrySet() .stream() .collect(Collectors.toMap( Map.Entry::getKey, item -> item.getValue().entrySet().stream() .collect(Collectors.toMap( Map.Entry::getKey, valueMapper, (o, n) -> o, LinkedHashMap::new )), (o, n) -> o, LinkedHashMap::new )); }