java.util.Map转化成scala.collection.immutable.Map

1.适用于jdk1.7+版本

public static scala.collection.immutable.Map toScalaImmutableMap(java.util.Map javaMap) {
        final java.util.List> list = new java.util.ArrayList<>(javaMap.size());
        for (final java.util.Map.Entry entry : javaMap.entrySet()) {
            list.add(scala.Tuple2.apply(entry.getKey(), entry.getValue()));
        }
        final scala.collection.Seq> seq = scala.collection.JavaConverters.asScalaBufferConverter(list).asScala().toSeq();
        return (scala.collection.immutable.Map) scala.collection.immutable.Map$.MODULE$.apply(seq);
    }

2.适用于jdk1.8+版本

public static  scala.collection.immutable.Map toScalaImmutableMap(java.util.Map jmap) {
        List> tuples = jmap.entrySet()
                .stream()
                .map(e -> Tuple2.apply(e.getKey(), e.getValue()))
                .collect(Collectors.toList());

        Seq> scalaSeq = scala.collection.JavaConverters.asScalaBufferConverter(tuples).asScala().toSeq()

        return (Map) scala.collection.immutable.Map$.MODULE$.apply(scalaSeq);
    }

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