Kafka函数中的class关键字

Question

我在火花流媒体应用程序中使用了一个java kafka函数

JavaInputDStream<Tuple2<String,String>> messages = KafkaUtils.createDirectStream(jssc,
                String.class,
                String.class,
                StringDecoder.class,
                StringDecoder.class,
                Tuple2.class,
                kafkaParams,
                fromOffsets,
                messageHandler);

记录输出与Tuple2的类型相同 由于

，上面给出了错误

Tuple2.class

错误说：

The method createDirectStream(JavaStreamingContext, Class<K>, Class<V>, Class<KD>, Class<VD>, Class<R>, Map<String,String>, Map<TopicAndPartition,Long>, Function<MessageAndMetadata<K,V>,R>) in the type KafkaUtils is not applicable for the arguments (JavaStreamingContext, Class<String>, Class<String>, Class<StringDecoder>, Class<StringDecoder>, Class<Tuple2>, Map<String,String>, Map<TopicAndPartition,Long>, Function<MessageAndMetadata<String,String>,Tuple2<String,String>>)

如何为Tuple2使用class关键字＆lt;字符串，字符串＆GT;