spark streaming 异常No output streams registered, so nothing to execute

实现spark streaming demo时，代码：

public static void main (String[] args) {


SparkConf conf = new SparkConf().setAppName("Spark_Streaming").setMaster("local");
        JavaSparkContext sc = new JavaSparkContext(conf);       
        JavaStreamingContext jssc = new JavaStreamingContext(sc, new Duration(2));      
        JavaSQLContext sqlCtx = new JavaSQLContext(sc);     


        String[] filters = new String[] {"soc"};

        JavaReceiverInputDStream<Status> receiverStream = TwitterUtils.createStream(jssc,filters);



         jssc.start();
         jssc.awaitTermination();

}

运行以上代码会出现异常：No output streams registered, so nothing to execute

原因是当发生输出操作的时候，会触发流计算操作，当在 DStream上没有输出操作或者计算时，通常需要执行某些操作，比如以任意方法：

print()
foreachRDD(func)
saveAsObjectFiles(prefix, [suffix])
saveAsTextFiles(prefix, [suffix])
saveAsHadoopFiles(prefix, [suffix])

 可参考：http://spark.apache.org/docs/latest/streaming-programming-guide.html#output-operations