带有DataFrame API的Apache Spark MLlib在createDataFrame（）或read（）时发出java.net.URISyntaxException。csv（...）

Question

在独立应用程序（在java8上运行，Windows 10 with spark-xxx_2.11：2.0。 0作为依赖的JAR）下一个代码给出了一个错误：

/* this: */ 
Dataset<Row> logData = spark_session.createDataFrame(Arrays.asList(
    new LabeledPoint(1.0, Vectors.dense(4.9,3,1.4,0.2)), 
    new LabeledPoint(1.0, Vectors.dense(4.7,3.2,1.3,0.2)) 
), LabeledPoint.class); 

/* or this: */ 
/* logFile: "C:\files\project\file.csv", "C:\\files\\project\\file.csv", 
      "C:/files/project/file.csv", "file:/C:/files/project/file.csv", 
      "file:///C:/files/project/file.csv", "/file.csv" */ 
Dataset<Row> logData = spark_session.read().csv(logFile); 

例外：

java.lang.IllegalArgumentException: java.net.URISyntaxException: Relative path in absolute URI: file:C:/files/project/spark-warehouse 
       at org.apache.hadoop.fs.Path.initialize(Path.java:206) 
       at org.apache.hadoop.fs.Path.<init>(Path.java:172) 
       at org.apache.spark.sql.catalyst.catalog.SessionCatalog.makeQualifiedPath(SessionCatalog.scala:114) 
       at org.apache.spark.sql.catalyst.catalog.SessionCatalog.createDatabase(SessionCatalog.scala:145) 
       at org.apache.spark.sql.catalyst.catalog.SessionCatalog.<init>(SessionCatalog.scala:89) 
       at org.apache.spark.sql.internal.SessionState.catalog$lzycompute(SessionState.scala:95) 
       at org.apache.spark.sql.internal.SessionState.catalog(SessionState.scala:95) 
       at org.apache.spark.sql.internal.SessionState$$anon$1.<init>(SessionState.scala:112) 
       at org.apache.spark.sql.internal.SessionState.analyzer$lzycompute(SessionState.scala:112) 
       at org.apache.spark.sql.internal.SessionState.analyzer(SessionState.scala:111) 
       at org.apache.spark.sql.execution.QueryExecution.assertAnalyzed(QueryExecution.scala:49) 
       at org.apache.spark.sql.Dataset$.ofRows(Dataset.scala:64) 
       at org.apache.spark.sql.SparkSession.createDataFrame(SparkSession.scala:373) 
       at <call in my line of code> 

我如何可以加载CSV文件导入Dataset<Row>从Java代码？

Answer 1

文件系统路径存在一些问题。请参阅jira https://issues.apache.org/jira/browse/SPARK-15899。对于解决方法，您可以在SparkSession中设置“spark.sql.warehouse.dir”，如下所示。

SparkSession spark = SparkSession 
    .builder() 
    .appName("JavaALSExample") 
    .config("spark.sql.warehouse.dir", "/file:C:/temp") 
    .getOrCreate();