Java spark映射方法引发序列化异常
我是Java spark映射方法引发序列化异常,java,hadoop,serialization,apache-spark,Java,Hadoop,Serialization,Apache Spark,我是Spark新手,我在map函数中遇到了序列化问题。下面是一些代码元素 private Function<Row, String> SparkMap() throws IOException { return new Function<Row, String>() { public String call(Row row) throws IOException { /* some code */
Spark
新手,我在map
函数中遇到了序列化问题。下面是一些代码元素
private Function<Row, String> SparkMap() throws IOException {
return new Function<Row, String>() {
public String call(Row row) throws IOException {
/* some code */
}
};
}
public static void main(String[] args) throws Exception {
MyClass myClass = new MyClass();
SQLContext sqlContext = new SQLContext(sc);
DataFrame df = sqlContext.load(args[0], "com.databricks.spark.avro");
JavaRDD<String> output = df.javaRDD().map(myClass.SparkMap());
}
private函数SparkMap()引发IOException{
返回新函数(){
公共字符串调用(行)引发IOException{
/*一些代码*/
}
};
}
公共静态void main(字符串[]args)引发异常{
MyClass MyClass=新的MyClass();
SQLContext SQLContext=新的SQLContext(sc);
DataFrame df=sqlContext.load(args[0],“com.databricks.spark.avro”);
JavaRDD output=df.JavaRDD().map(myClass.SparkMap());
}
这是错误日志
Caused by: java.io.NotSerializableException: myPackage.MyClass
Serialization stack:
- object not serializable (class: myPackage.MyClass, value: myPackage.MyClass@281c8380)
- field (class: myPackage.MyClass$1, name: this$0, type: class myPackage.MyClass)
- object (class myPackage.MyClass$1, myPackage.MyClass$1@28ef1bc8)
- field (class: org.apache.spark.api.java.JavaPairRDD$$anonfun$toScalaFunction$1, name: fun$1, type: interface org.apache.spark.api.java.function.Function)
- object (class org.apache.spark.api.java.JavaPairRDD$$anonfun$toScalaFunction$1, <function1>)
at org.apache.spark.serializer.SerializationDebugger$.improveException(SerializationDebugger.scala:40)
at org.apache.spark.serializer.JavaSerializationStream.writeObject(JavaSerializer.scala:47)
at org.apache.spark.serializer.JavaSerializerInstance.serialize(JavaSerializer.scala:81)
at org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:312)
... 12 more
原因:java.io.NotSerializableException:myPackage.MyClass
序列化堆栈:
-对象不可序列化(类:myPackage.MyClass,值:myPackage)。MyClass@281c8380)
-字段(类:myPackage.MyClass$1,名称:this$0,类型:class myPackage.MyClass)
-对象(类myPackage.MyClass$1,myPackage.MyClass$1@28ef1bc8)
-字段(类:org.apache.spark.api.java.javapairdd$$anonfun$toScalaFunction$1,名称:fun$1,类型:interface org.apache.spark.api.java.function.function)
-对象(类org.apache.spark.api.java.javapairdd$$anonfun$toScalaFunction$1,)
位于org.apache.spark.serializer.SerializationDebugger$.ImproveeException(SerializationDebugger.scala:40)
位于org.apache.spark.serializer.JavaSerializationStream.writeObject(JavaSerializer.scala:47)
位于org.apache.spark.serializer.JavaSerializerInstance.serialize(JavaSerializer.scala:81)
位于org.apache.spark.util.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:312)
... 还有12个
如果我声明
SparkMap
方法是静态的,那么它将运行。这怎么可能呢?例外情况很容易解释:
object not serializable (class: myPackage.MyClass, value: myPackage.MyClass@281c8380)
只需将您的MyClas
sSerializable
设置为可序列化即可
它是静态的,因为在这种情况下它只接受函数,而不是整个myClass
对象