SparkStreaming報錯: Only one SparkContext may be running in this JVM (see SPARK-2243)

報錯資訊：

Exception in thread "main" org.apache.spark.SparkException: 
Only one SparkContext may be running in this JVM (see SPARK-2243). 
To ignore this error, set spark.driver.allowMultipleContexts = true. 
The currently running SparkContext was created at:
org.apache.spark.api.java.JavaSparkContext

原因：

出現這個問題的原因就是你建立了多個 SparkContext ,就像下面這種用法,只需要幹掉J avaSparkContext 就可:

SparkConf conf = new SparkConf()
   			.setAppName(“myapplication”).setMaster(“local[4]”);
JavaSparkContext jsc = new JavaSparkContext(conf);
JavaStreamingContext stream = new JavaStreamingContext(conf, Durations.seconds(10));

解決這個問題兩種方式:

方式1：

SparkConf conf = new SparkConf()
				.setAppName(“myapplication”)  .setMaster(“local[4]”);
 JavaStreamingContext stream = new JavaStreamingContext(conf, Durations.seconds(10));

方式2：

SparkConf conf = new SparkConf()
.setAppName(“myapplication”).setMaster(“local[4]”);
JavaSparkContext jsc = new JavaSparkContext(conf);
JavaStreamingContext stream = new JavaStreamingContext(jsc, Durations.seconds(10));