scala - 由 : java. lang.IllegalArgumentException 引起:无法为 null 获取 JDBC 类型

Question

加载 Null 时出现以下错误spark 中数据库的值。 Datatype目标表是 smallint

Caused by: java.lang.IllegalArgumentException: Can't get JDBC type for null

代码 :

val hivedata = spark.sql(s"""select 1 as column1 , B a column2 , NULL as column3 from table""")

hivedata .write.mode(SaveMode.Append).jdbc(url = con, table = targettable, Pconnectionropertiess)

谁能帮帮我吗

Answer 1

cast(NULL as smallint)你必须做...这会将 null 转换为 short类型如下图所示。

val df1 =spark.sql(
     " select 1 as column1 , 2 column2 , cast(NULL as smallint) as column3 from table  ")
  df1.show
df1.printSchema()

结果 :

+-------+-------+-------+
|column1|column2|column3|
+-------+-------+-------+
|      1|      2|   null|
+-------+-------+-------+

root
 |-- column1: integer (nullable = false)
 |-- column2: integer (nullable = false)
 |-- column3: short (nullable = true)

否则你的方式它将是空类型而不是小整数类型..

val df1 =spark.sql(" select 1 as column1 , 2 column2 ,  NULL   as column3 from table  ")
  df1.show
df1.printSchema()

+-------+-------+-------+
|column1|column2|column3|
+-------+-------+-------+
|      1|      2|   null|
+-------+-------+-------+

root
 |-- column1: integer (nullable = false)
 |-- column2: integer (nullable = false)
 |-- column3: null (nullable = true)

这就是您收到异常的原因。