我正在尝试使用Java解决HashMaps的Spark序列化问题。 我指的是Save Spark Dataframe into Elasticsearch - Can’t handle type exception链接。
现在我遇到了以下问题:
java.lang.ClassCastException: com.spark.util.umf.MyKryoRegistrator cannot be cast to org.apache.spark.serializer.Serializer at org.apache.spark.SparkEnv$.create(SparkEnv.scala:259) at org.apache.spark.SparkEnv$.createDriverEnv(SparkEnv.scala:163) at org.apache.spark.SparkContext.createSparkEnv(SparkContext.scala:267) at org.apache.spark.SparkContext.(SparkContext.scala:270) at org.apache.spark.api.java.JavaSparkContext.JavaSparkContext.scala:61) at com.spark.util.umf.MyMain.main(MyMain.java:46) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.spark.deploy.yarn.ApplicationMaster$$anon$2.run(ApplicationMaster.scala:480) 15/10/16 01:47:22 INFO yarn.ApplicationMaster: Final app status: FAILED, exitCode: 15, (reason: User class threw exception: com.spark.util.umf.MyKryoRegistrator cannot be cast to org.apache.spark.serializer.Serializer)
我创建了Kryo
registrator,如下所示:
import java.io.Serializable;
import org.apache.spark.serializer.KryoRegistrator;
import com.esotericsoftware.kryo.Kryo;
public class MyKryoRegistrator implements KryoRegistrator, Serializable {
@Override
public void registerClasses(Kryo kryo) {
// Product POJO associated to a product Row from the DataFrame
kryo.register(MyRecord.class);
}
}
主要方法:
public static void main(String args[]){
SparkConf sConf= new SparkConf().setAppName("SparkTestJob");
sConf.set( "spark.driver.allowMultipleContexts", "true");
//Kryo kryo = new Kryo();;
//kryo.setDefaultSerializer(MyRecord.class);
//my.registerClasses(kryo);
sConf.set("spark.serializer","com.spark.util.umf.MyKryoRegistrator");
[...]
}
答案 0 :(得分:3)
根据您在问题中提到的链接中提供的答案,您可以看到我已经定义了这两个参数:
spark.serializer
和spark.kryo.registrator
所以你必须设置两个参数。
如果在未设置序列化程序的情况下设置registrator,则不会设置kryo序列化程序。