我安装了以下版本： - 火花2.1.0， 斯卡拉2.11.6， mongoDB 3.2.17
我尝试使用以下命令启动pyspark shell
./bin/pyspark --packages org.mongodb.spark:mongo-spark-connector_2.11:2.2.0
在此之后我开始如下火花会议
from pyspark.sql import SparkSession
my_spark = SparkSession.builder.appName("myApp").config("spark.mongodb.input.uri", "mongodb://127.0.0.1/mycollection.dummy").config("spark.mongodb.output.uri", "mongodb://127.0.0.1/mycollection.dummy").getOrCreate()
我在mongodb db中执行了对集合的写入，并且它已成功执行
但是，当我尝试使用命令
读取集合时df = my_spark.read.format("com.mongodb.spark.sql.DefaultSource").option("uri","mongodb://127.0.0.1/mycollection.dummy").load()
显示错误如下
17/10/13 10:43:33 ERROR executor.Executor: Exception in task 0.0 in stage 2.0 (TID 2)
java.lang.NoSuchMethodError: org.apache.spark.sql.catalyst.analysis.TypeCoercion$.findTightestCommonType()Lscala/Function2;
at com.mongodb.spark.sql.MongoInferSchema$.com$mongodb$spark$sql$MongoInferSchema$$compatibleType(MongoInferSchema.scala:135)
at com.mongodb.spark.sql.MongoInferSchema$$anonfun$3.apply(MongoInferSchema.scala:78)
at com.mongodb.spark.sql.MongoInferSchema$$anonfun$3.apply(MongoInferSchema.scala:78)
at scala.collection.TraversableOnce$$anonfun$foldLeft$1.apply(TraversableOnce.scala:157)
at scala.collection.TraversableOnce$$anonfun$foldLeft$1.apply(TraversableOnce.scala:157)
at scala.collection.Iterator$class.foreach(Iterator.scala:893)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
at scala.collection.TraversableOnce$class.foldLeft(TraversableOnce.scala:157)
at scala.collection.AbstractIterator.foldLeft(Iterator.scala:1336)
at scala.collection.TraversableOnce$class.aggregate(TraversableOnce.scala:214)
at scala.collection.AbstractIterator.aggregate(Iterator.scala:1336)
at org.apache.spark.rdd.RDD$$anonfun$treeAggregate$1$$anonfun$24.apply(RDD.scala:1135)
at org.apache.spark.rdd.RDD$$anonfun$treeAggregate$1$$anonfun$24.apply(RDD.scala:1135)
at org.apache.spark.rdd.RDD$$anonfun$treeAggregate$1$$anonfun$25.apply(RDD.scala:1136)
at org.apache.spark.rdd.RDD$$anonfun$treeAggregate$1$$anonfun$25.apply(RDD.scala:1136)
at org.apache.spark.rdd.RDD$$anonfun$mapPartitions$1$$anonfun$apply$23.apply(RDD.scala:796)
at org.apache.spark.rdd.RDD$$anonfun$mapPartitions$1$$anonfun$apply$23.apply(RDD.scala:796)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
at org.apache.spark.scheduler.Task.run(Task.scala:99)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:282)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
答案 0 :(得分：0)
您似乎在数据框读取线中存在不一致。首先，您初始化spark，然后使用"uri"。您还使用"spark.mongodb.input.uri"，而不是df = my_spark.read.format("com.mongodb.spark.sql.DefaultSource").option("spark.mongodb.input.uri","mongodb://127.0.0.1/mycollection.dummy").load()
。请尝试以下方法：
fromgroupName否则提供更多代码作为整体检查。