[Java] 比較 json 文件

import java.util.AbstractMap.SimpleEntry;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public final class FlatMapUtil {

    private FlatMapUtil() {
        throw new AssertionError("No instances for you!");
    }

    public static Map<String, Object> flatten(Map<String, Object> map) {
        return map.entrySet()
                .stream()
                .flatMap(FlatMapUtil::flatten)
                .collect(LinkedHashMap::new, (m, e) -> m.put("/" + e.getKey(), e.getValue()), LinkedHashMap::putAll);
    }

    private static Stream<Entry<String, Object>> flatten(Entry<String, Object> entry) {

        if (entry == null) {
            return Stream.empty();
        }

        if (entry.getValue() instanceof Map<?, ?>) {
            Map<?, ?> properties = (Map<?, ?>) entry.getValue();
            return properties.entrySet()
                    .stream()
                    .flatMap(e -> flatten(new SimpleEntry<>(entry.getKey() + "/" + e.getKey(), e.getValue())));
        }

        if (entry.getValue() instanceof List<?>) {
            List<?> list = (List<?>) entry.getValue();
            return IntStream.range(0, list.size())
                    .mapToObj(i -> new SimpleEntry<String, Object>(entry.getKey() + "/" + i, list.get(i)))
                    .flatMap(FlatMapUtil::flatten);
        }

        return Stream.of(entry);
    }
}

Map<String, Object> leftFlatMap = FlatMapUtil.flatten(leftMap);
Map<String, Object> rightFlatMap = FlatMapUtil.flatten(rightMap);

MapDifference<String, Object> difference = Maps.difference(leftFlatMap, rightFlatMap);

System.out.println("Entries only on left\n--------------------------");
difference.entriesOnlyOnLeft().forEach((key, value) -> System.out.println(key + ": " + value));

System.out.println("\n\nEntries only on right\n--------------------------");
difference.entriesOnlyOnRight().forEach((key, value) -> System.out.println(key + ": " + value));

System.out.println("\n\nEntries differing\n--------------------------");
difference.entriesDiffering().forEach((key, value) -> System.out.println(key + ": " + value));

System.out.println("\n\nEntries in common\n--------------------------");
difference.entriesInCommon().forEach((key, value) -> System.out.println(key + ": " + value));