使用 pyspark 从 cassandra 获取数据时出错
Error while fetching data from cassandra using pyspark
我是 apache spark 的新手，我只需要从 cassandra 数据库中获取一个 table，下面我附加了数据来调试情况，请帮助并提前感谢。
卡桑德拉 Node:192.168.56.10
星火节点：192.168.56.10
要获取的 Cassandra Table：dev.device {keyspace.table_name}
通过连接到 cassandra 访问 pyspark：
[root@spark ~]# pyspark --packages com.datastax.spark:spark-cassandra-connector_2.11:3.0-alpha --conf spark.cassandra.connection.host=192.168.56.10
Python 3.6.8 (default, Nov 9 2021, 14:44:26)
[GCC 8.5.0 20210514 (Red Hat 8.5.0-3)] on linux
Type "help", "copyright", "credits" or "license" for more information.
:: loading settings :: url = jar:file:/opt/spark-3.2.0-bin-hadoop3.2/jars/ivy-2.5.0.jar!/org/apache/ivy/core/settings/ivysettings.xml
Ivy Default Cache set to: /root/.ivy2/cache
The jars for the packages stored in: /root/.ivy2/jars
com.datastax.spark#spark-cassandra-connector_2.11 added as a dependency
:: resolving dependencies :: org.apache.spark#spark-submit-parent-4c386c5c-716c-4c28-bc76-ae5870833da2;1.0
confs: [default]
found com.datastax.spark#spark-cassandra-connector_2.11;3.0-alpha in central
found com.datastax.spark#spark-cassandra-connector-driver_2.11;3.0-alpha in central
found com.datastax.oss#java-driver-core-shaded;4.5.0 in central
found com.datastax.oss#native-protocol;1.4.9 in central
found com.datastax.oss#java-driver-shaded-guava;25.1-jre in central
found com.typesafe#config;1.3.4 in central
found com.github.jnr#jnr-ffi;2.1.10 in central
found com.github.jnr#jffi;1.2.19 in central
found org.ow2.asm#asm;7.1 in central
found org.ow2.asm#asm-commons;7.1 in central
found org.ow2.asm#asm-tree;7.1 in central
found org.ow2.asm#asm-analysis;7.1 in central
found org.ow2.asm#asm-util;7.1 in central
found com.github.jnr#jnr-a64asm;1.0.0 in central
found com.github.jnr#jnr-x86asm;1.0.2 in central
found com.github.jnr#jnr-posix;3.0.50 in central
found com.github.jnr#jnr-constants;0.9.12 in central
found org.slf4j#slf4j-api;1.7.26 in central
found io.dropwizard.metrics#metrics-core;4.0.5 in central
found org.hdrhistogram#HdrHistogram;2.1.11 in central
found org.apache.tinkerpop#gremlin-core;3.4.5 in central
found org.apache.tinkerpop#gremlin-shaded;3.4.5 in central
found commons-configuration#commons-configuration;1.10 in central
found commons-lang#commons-lang;2.6 in central
found commons-collections#commons-collections;3.2.2 in central
found org.yaml#snakeyaml;1.15 in central
found org.javatuples#javatuples;1.2 in central
found com.carrotsearch#hppc;0.7.1 in central
found com.jcabi#jcabi-manifests;1.1 in central
found com.jcabi#jcabi-log;0.14 in central
found com.squareup#javapoet;1.11.1 in central
found net.objecthunter#exp4j;0.4.8 in central
found org.slf4j#jcl-over-slf4j;1.7.25 in central
found org.apache.tinkerpop#gremlin-driver;3.4.5 in central
found org.codehaus.groovy#groovy;2.5.7 in central
found org.codehaus.groovy#groovy-json;2.5.7 in central
found org.apache.tinkerpop#tinkergraph-gremlin;3.4.5 in central
found org.reactivestreams#reactive-streams;1.0.2 in central
found com.github.stephenc.jcip#jcip-annotations;1.0-1 in central
found com.github.spotbugs#spotbugs-annotations;3.1.12 in central
found com.google.code.findbugs#jsr305;3.0.2 in central
found com.datastax.oss#java-driver-mapper-runtime;4.5.0 in central
found com.datastax.oss#java-driver-query-builder;4.5.0 in central
found org.apache.commons#commons-lang3;3.5 in central
found com.thoughtworks.paranamer#paranamer;2.8 in central
found com.typesafe.scala-logging#scala-logging_2.11;3.5.0 in central
found org.scala-lang#scala-reflect;2.11.12 in central
:: resolution report :: resolve 1099ms :: artifacts dl 30ms
:: modules in use:
com.carrotsearch#hppc;0.7.1 from central in [default]
com.datastax.oss#java-driver-core-shaded;4.5.0 from central in [default]
com.datastax.oss#java-driver-mapper-runtime;4.5.0 from central in [default]
com.datastax.oss#java-driver-query-builder;4.5.0 from central in [default]
com.datastax.oss#java-driver-shaded-guava;25.1-jre from central in [default]
com.datastax.oss#native-protocol;1.4.9 from central in [default]
com.datastax.spark#spark-cassandra-connector-driver_2.11;3.0-alpha from central in [default]
com.datastax.spark#spark-cassandra-connector_2.11;3.0-alpha from central in [default]
com.github.jnr#jffi;1.2.19 from central in [default]
com.github.jnr#jnr-a64asm;1.0.0 from central in [default]
com.github.jnr#jnr-constants;0.9.12 from central in [default]
com.github.jnr#jnr-ffi;2.1.10 from central in [default]
com.github.jnr#jnr-posix;3.0.50 from central in [default]
com.github.jnr#jnr-x86asm;1.0.2 from central in [default]
com.github.spotbugs#spotbugs-annotations;3.1.12 from central in [default]
com.github.stephenc.jcip#jcip-annotations;1.0-1 from central in [default]
com.google.code.findbugs#jsr305;3.0.2 from central in [default]
com.jcabi#jcabi-log;0.14 from central in [default]
com.jcabi#jcabi-manifests;1.1 from central in [default]
com.squareup#javapoet;1.11.1 from central in [default]
com.thoughtworks.paranamer#paranamer;2.8 from central in [default]
com.typesafe#config;1.3.4 from central in [default]
com.typesafe.scala-logging#scala-logging_2.11;3.5.0 from central in [default]
commons-collections#commons-collections;3.2.2 from central in [default]
commons-configuration#commons-configuration;1.10 from central in [default]
commons-lang#commons-lang;2.6 from central in [default]
io.dropwizard.metrics#metrics-core;4.0.5 from central in [default]
net.objecthunter#exp4j;0.4.8 from central in [default]
org.apache.commons#commons-lang3;3.5 from central in [default]
org.apache.tinkerpop#gremlin-core;3.4.5 from central in [default]
org.apache.tinkerpop#gremlin-driver;3.4.5 from central in [default]
org.apache.tinkerpop#gremlin-shaded;3.4.5 from central in [default]
org.apache.tinkerpop#tinkergraph-gremlin;3.4.5 from central in [default]
org.codehaus.groovy#groovy;2.5.7 from central in [default]
org.codehaus.groovy#groovy-json;2.5.7 from central in [default]
org.hdrhistogram#HdrHistogram;2.1.11 from central in [default]
org.javatuples#javatuples;1.2 from central in [default]
org.ow2.asm#asm;7.1 from central in [default]
org.ow2.asm#asm-analysis;7.1 from central in [default]
org.ow2.asm#asm-commons;7.1 from central in [default]
org.ow2.asm#asm-tree;7.1 from central in [default]
org.ow2.asm#asm-util;7.1 from central in [default]
org.reactivestreams#reactive-streams;1.0.2 from central in [default]
org.scala-lang#scala-reflect;2.11.12 from central in [default]
org.slf4j#jcl-over-slf4j;1.7.25 from central in [default]
org.slf4j#slf4j-api;1.7.26 from central in [default]
org.yaml#snakeyaml;1.15 from central in [default]
:: evicted modules:
org.apache.commons#commons-lang3;3.8.1 by [org.apache.commons#commons-lang3;3.5] in [default]
org.scala-lang#scala-reflect;2.11.8 by [org.scala-lang#scala-reflect;2.11.12] in [default]
org.slf4j#slf4j-api;1.7.21 by [org.slf4j#slf4j-api;1.7.26] in [default]
---------------------------------------------------------------------
| | modules || artifacts |
| conf | number| search|dwnlded|evicted|| number|dwnlded|
---------------------------------------------------------------------
| default | 50 | 0 | 0 | 3 || 47 | 0 |
---------------------------------------------------------------------
:: retrieving :: org.apache.spark#spark-submit-parent-4c386c5c-716c-4c28-bc76-ae5870833da2
confs: [default]
0 artifacts copied, 47 already retrieved (0kB/32ms)
21/12/27 14:11:11 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Using Spark's default log4j profile: org/apache/spark/log4j-defaults.properties
Setting default log level to "WARN".
To adjust logging level use sc.setLogLevel(newLevel). For SparkR, use setLogLevel(newLevel).
21/12/27 14:11:13 WARN Utils: Service 'SparkUI' could not bind on port 4040. Attempting port 4041.
/opt/spark-3.2.0-bin-hadoop3.2/python/pyspark/context.py:238: FutureWarning: Python 3.6 support is deprecated in Spark 3.2.
FutureWarning
Welcome to
____ __
/ __/__ ___ _____/ /__
_\ \/ _ \/ _ `/ __/ '_/
/__ / .__/\_,_/_/ /_/\_\ version 3.2.0
/_/
Using Python version 3.6.8 (default, Nov 9 2021 14:44:26)
Spark context Web UI available at http://spark.localdomain:4041
Spark context available as 'sc' (master = spark://spark:7077, app id = app-20211227141113-0011).
SparkSession available as 'spark'.
>>>
访问cassandra的代码table和错误：
>>> from pyspark.sql import SQLContext
>>> load_options = { "table": "device", "keyspace": "dev"}
>>> df=spark.read.format("org.apache.spark.sql.cassandra").options(**load_options).load()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/opt/spark-3.2.0-bin-hadoop3.2/python/pyspark/sql/readwriter.py", line 164, in load
return self._df(self._jreader.load())
File "/opt/spark-3.2.0-bin-hadoop3.2/python/lib/py4j-0.10.9.2-src.zip/py4j/java_gateway.py", line 1310, in __call__
File "/opt/spark-3.2.0-bin-hadoop3.2/python/pyspark/sql/utils.py", line 111, in deco
return f(*a, **kw)
File "/opt/spark-3.2.0-bin-hadoop3.2/python/lib/py4j-0.10.9.2-src.zip/py4j/protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o44.load.
: java.lang.NoClassDefFoundError: scala/Product$class
at com.datastax.spark.connector.TableRef.<init>(TableRef.scala:4)
at org.apache.spark.sql.cassandra.DefaultSource$.TableRefAndOptions(DefaultSource.scala:142)
at org.apache.spark.sql.cassandra.DefaultSource.createRelation(DefaultSource.scala:56)
at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:350)
at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:274)
at org.apache.spark.sql.DataFrameReader.$anonfun$load(DataFrameReader.scala:245)
at scala.Option.getOrElse(Option.scala:189)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:245)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:174)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
at py4j.Gateway.invoke(Gateway.java:282)
at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
at py4j.commands.CallCommand.execute(CallCommand.java:79)
at py4j.ClientServerConnection.waitForCommands(ClientServerConnection.java:182)
at py4j.ClientServerConnection.run(ClientServerConnection.java:106)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: scala.Product$class
at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 21 more
>>> df.show()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'df' is not defined
>>>
谁能指出这里有什么问题吗？
您不能将为 Scala 2.11 编译的连接器与使用 Scala 2.12 编译的 Spark 3.2.0 一起使用。您需要使用适当的版本 - right now it's 3.1.0 坐标 com.datastax.spark:spark-cassandra-connector_2.12:3.1.0
P.S。请注意，虽然基本功能可以使用，但在修复 SPARKC-670 之前更高级的功能将无法使用（参见 this PR）
我是 apache spark 的新手，我只需要从 cassandra 数据库中获取一个 table，下面我附加了数据来调试情况，请帮助并提前感谢。 卡桑德拉 Node:192.168.56.10 星火节点：192.168.56.10
要获取的 Cassandra Table：dev.device {keyspace.table_name}
通过连接到 cassandra 访问 pyspark：
[root@spark ~]# pyspark --packages com.datastax.spark:spark-cassandra-connector_2.11:3.0-alpha --conf spark.cassandra.connection.host=192.168.56.10
Python 3.6.8 (default, Nov 9 2021, 14:44:26)
[GCC 8.5.0 20210514 (Red Hat 8.5.0-3)] on linux
Type "help", "copyright", "credits" or "license" for more information.
:: loading settings :: url = jar:file:/opt/spark-3.2.0-bin-hadoop3.2/jars/ivy-2.5.0.jar!/org/apache/ivy/core/settings/ivysettings.xml
Ivy Default Cache set to: /root/.ivy2/cache
The jars for the packages stored in: /root/.ivy2/jars
com.datastax.spark#spark-cassandra-connector_2.11 added as a dependency
:: resolving dependencies :: org.apache.spark#spark-submit-parent-4c386c5c-716c-4c28-bc76-ae5870833da2;1.0
confs: [default]
found com.datastax.spark#spark-cassandra-connector_2.11;3.0-alpha in central
found com.datastax.spark#spark-cassandra-connector-driver_2.11;3.0-alpha in central
found com.datastax.oss#java-driver-core-shaded;4.5.0 in central
found com.datastax.oss#native-protocol;1.4.9 in central
found com.datastax.oss#java-driver-shaded-guava;25.1-jre in central
found com.typesafe#config;1.3.4 in central
found com.github.jnr#jnr-ffi;2.1.10 in central
found com.github.jnr#jffi;1.2.19 in central
found org.ow2.asm#asm;7.1 in central
found org.ow2.asm#asm-commons;7.1 in central
found org.ow2.asm#asm-tree;7.1 in central
found org.ow2.asm#asm-analysis;7.1 in central
found org.ow2.asm#asm-util;7.1 in central
found com.github.jnr#jnr-a64asm;1.0.0 in central
found com.github.jnr#jnr-x86asm;1.0.2 in central
found com.github.jnr#jnr-posix;3.0.50 in central
found com.github.jnr#jnr-constants;0.9.12 in central
found org.slf4j#slf4j-api;1.7.26 in central
found io.dropwizard.metrics#metrics-core;4.0.5 in central
found org.hdrhistogram#HdrHistogram;2.1.11 in central
found org.apache.tinkerpop#gremlin-core;3.4.5 in central
found org.apache.tinkerpop#gremlin-shaded;3.4.5 in central
found commons-configuration#commons-configuration;1.10 in central
found commons-lang#commons-lang;2.6 in central
found commons-collections#commons-collections;3.2.2 in central
found org.yaml#snakeyaml;1.15 in central
found org.javatuples#javatuples;1.2 in central
found com.carrotsearch#hppc;0.7.1 in central
found com.jcabi#jcabi-manifests;1.1 in central
found com.jcabi#jcabi-log;0.14 in central
found com.squareup#javapoet;1.11.1 in central
found net.objecthunter#exp4j;0.4.8 in central
found org.slf4j#jcl-over-slf4j;1.7.25 in central
found org.apache.tinkerpop#gremlin-driver;3.4.5 in central
found org.codehaus.groovy#groovy;2.5.7 in central
found org.codehaus.groovy#groovy-json;2.5.7 in central
found org.apache.tinkerpop#tinkergraph-gremlin;3.4.5 in central
found org.reactivestreams#reactive-streams;1.0.2 in central
found com.github.stephenc.jcip#jcip-annotations;1.0-1 in central
found com.github.spotbugs#spotbugs-annotations;3.1.12 in central
found com.google.code.findbugs#jsr305;3.0.2 in central
found com.datastax.oss#java-driver-mapper-runtime;4.5.0 in central
found com.datastax.oss#java-driver-query-builder;4.5.0 in central
found org.apache.commons#commons-lang3;3.5 in central
found com.thoughtworks.paranamer#paranamer;2.8 in central
found com.typesafe.scala-logging#scala-logging_2.11;3.5.0 in central
found org.scala-lang#scala-reflect;2.11.12 in central
:: resolution report :: resolve 1099ms :: artifacts dl 30ms
:: modules in use:
com.carrotsearch#hppc;0.7.1 from central in [default]
com.datastax.oss#java-driver-core-shaded;4.5.0 from central in [default]
com.datastax.oss#java-driver-mapper-runtime;4.5.0 from central in [default]
com.datastax.oss#java-driver-query-builder;4.5.0 from central in [default]
com.datastax.oss#java-driver-shaded-guava;25.1-jre from central in [default]
com.datastax.oss#native-protocol;1.4.9 from central in [default]
com.datastax.spark#spark-cassandra-connector-driver_2.11;3.0-alpha from central in [default]
com.datastax.spark#spark-cassandra-connector_2.11;3.0-alpha from central in [default]
com.github.jnr#jffi;1.2.19 from central in [default]
com.github.jnr#jnr-a64asm;1.0.0 from central in [default]
com.github.jnr#jnr-constants;0.9.12 from central in [default]
com.github.jnr#jnr-ffi;2.1.10 from central in [default]
com.github.jnr#jnr-posix;3.0.50 from central in [default]
com.github.jnr#jnr-x86asm;1.0.2 from central in [default]
com.github.spotbugs#spotbugs-annotations;3.1.12 from central in [default]
com.github.stephenc.jcip#jcip-annotations;1.0-1 from central in [default]
com.google.code.findbugs#jsr305;3.0.2 from central in [default]
com.jcabi#jcabi-log;0.14 from central in [default]
com.jcabi#jcabi-manifests;1.1 from central in [default]
com.squareup#javapoet;1.11.1 from central in [default]
com.thoughtworks.paranamer#paranamer;2.8 from central in [default]
com.typesafe#config;1.3.4 from central in [default]
com.typesafe.scala-logging#scala-logging_2.11;3.5.0 from central in [default]
commons-collections#commons-collections;3.2.2 from central in [default]
commons-configuration#commons-configuration;1.10 from central in [default]
commons-lang#commons-lang;2.6 from central in [default]
io.dropwizard.metrics#metrics-core;4.0.5 from central in [default]
net.objecthunter#exp4j;0.4.8 from central in [default]
org.apache.commons#commons-lang3;3.5 from central in [default]
org.apache.tinkerpop#gremlin-core;3.4.5 from central in [default]
org.apache.tinkerpop#gremlin-driver;3.4.5 from central in [default]
org.apache.tinkerpop#gremlin-shaded;3.4.5 from central in [default]
org.apache.tinkerpop#tinkergraph-gremlin;3.4.5 from central in [default]
org.codehaus.groovy#groovy;2.5.7 from central in [default]
org.codehaus.groovy#groovy-json;2.5.7 from central in [default]
org.hdrhistogram#HdrHistogram;2.1.11 from central in [default]
org.javatuples#javatuples;1.2 from central in [default]
org.ow2.asm#asm;7.1 from central in [default]
org.ow2.asm#asm-analysis;7.1 from central in [default]
org.ow2.asm#asm-commons;7.1 from central in [default]
org.ow2.asm#asm-tree;7.1 from central in [default]
org.ow2.asm#asm-util;7.1 from central in [default]
org.reactivestreams#reactive-streams;1.0.2 from central in [default]
org.scala-lang#scala-reflect;2.11.12 from central in [default]
org.slf4j#jcl-over-slf4j;1.7.25 from central in [default]
org.slf4j#slf4j-api;1.7.26 from central in [default]
org.yaml#snakeyaml;1.15 from central in [default]
:: evicted modules:
org.apache.commons#commons-lang3;3.8.1 by [org.apache.commons#commons-lang3;3.5] in [default]
org.scala-lang#scala-reflect;2.11.8 by [org.scala-lang#scala-reflect;2.11.12] in [default]
org.slf4j#slf4j-api;1.7.21 by [org.slf4j#slf4j-api;1.7.26] in [default]
---------------------------------------------------------------------
| | modules || artifacts |
| conf | number| search|dwnlded|evicted|| number|dwnlded|
---------------------------------------------------------------------
| default | 50 | 0 | 0 | 3 || 47 | 0 |
---------------------------------------------------------------------
:: retrieving :: org.apache.spark#spark-submit-parent-4c386c5c-716c-4c28-bc76-ae5870833da2
confs: [default]
0 artifacts copied, 47 already retrieved (0kB/32ms)
21/12/27 14:11:11 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Using Spark's default log4j profile: org/apache/spark/log4j-defaults.properties
Setting default log level to "WARN".
To adjust logging level use sc.setLogLevel(newLevel). For SparkR, use setLogLevel(newLevel).
21/12/27 14:11:13 WARN Utils: Service 'SparkUI' could not bind on port 4040. Attempting port 4041.
/opt/spark-3.2.0-bin-hadoop3.2/python/pyspark/context.py:238: FutureWarning: Python 3.6 support is deprecated in Spark 3.2.
FutureWarning
Welcome to
____ __
/ __/__ ___ _____/ /__
_\ \/ _ \/ _ `/ __/ '_/
/__ / .__/\_,_/_/ /_/\_\ version 3.2.0
/_/
Using Python version 3.6.8 (default, Nov 9 2021 14:44:26)
Spark context Web UI available at http://spark.localdomain:4041
Spark context available as 'sc' (master = spark://spark:7077, app id = app-20211227141113-0011).
SparkSession available as 'spark'.
>>>
访问cassandra的代码table和错误：
>>> from pyspark.sql import SQLContext
>>> load_options = { "table": "device", "keyspace": "dev"}
>>> df=spark.read.format("org.apache.spark.sql.cassandra").options(**load_options).load()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/opt/spark-3.2.0-bin-hadoop3.2/python/pyspark/sql/readwriter.py", line 164, in load
return self._df(self._jreader.load())
File "/opt/spark-3.2.0-bin-hadoop3.2/python/lib/py4j-0.10.9.2-src.zip/py4j/java_gateway.py", line 1310, in __call__
File "/opt/spark-3.2.0-bin-hadoop3.2/python/pyspark/sql/utils.py", line 111, in deco
return f(*a, **kw)
File "/opt/spark-3.2.0-bin-hadoop3.2/python/lib/py4j-0.10.9.2-src.zip/py4j/protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o44.load.
: java.lang.NoClassDefFoundError: scala/Product$class
at com.datastax.spark.connector.TableRef.<init>(TableRef.scala:4)
at org.apache.spark.sql.cassandra.DefaultSource$.TableRefAndOptions(DefaultSource.scala:142)
at org.apache.spark.sql.cassandra.DefaultSource.createRelation(DefaultSource.scala:56)
at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:350)
at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:274)
at org.apache.spark.sql.DataFrameReader.$anonfun$load(DataFrameReader.scala:245)
at scala.Option.getOrElse(Option.scala:189)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:245)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:174)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
at py4j.Gateway.invoke(Gateway.java:282)
at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
at py4j.commands.CallCommand.execute(CallCommand.java:79)
at py4j.ClientServerConnection.waitForCommands(ClientServerConnection.java:182)
at py4j.ClientServerConnection.run(ClientServerConnection.java:106)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: scala.Product$class
at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 21 more
>>> df.show()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'df' is not defined
>>>
谁能指出这里有什么问题吗？
您不能将为 Scala 2.11 编译的连接器与使用 Scala 2.12 编译的 Spark 3.2.0 一起使用。您需要使用适当的版本 - right now it's 3.1.0 坐标 com.datastax.spark:spark-cassandra-connector_2.12:3.1.0
P.S。请注意，虽然基本功能可以使用，但在修复 SPARKC-670 之前更高级的功能将无法使用（参见 this PR）