我在Scala中创建了Serializable版本的Guava＆＃39 {s} ImmutableRangeMap和Builder，以便在我的Spark应用程序中使用。我的SerializableImmutableRangeMap中也有一个零参数构造函数，那么为什么我在运行Spark应用程序时会得到InvalidClassException: no valid constructor？
这是我的SerializableImmutableRangeClass对象和类：
object SerializableImmutableRangeMap extends Serializable {
final class SerializableBuilder[K <: Comparable[_], V]() extends Serializable {
val keyRanges: RangeSet[K] = TreeRangeSet.create()
val rangeMap: RangeMap[K, V] = TreeRangeMap.create()
def put(range: Range[K], value: V): SerializableBuilder[K, V] = {
checkNotNull(range)
checkNotNull(value)
checkArgument(!range.isEmpty(), "Range must not be empty, but was %s", range)
if (!keyRanges.complement().encloses(range)) {
// it's an error case; we can afford an expensive lookup
for (entry: Entry[Range[K], V] <- JavaConversions.asScalaSet(rangeMap.asMapOfRanges().entrySet())) {
val key: Range[K] = entry.getKey()
if (key.isConnected(range) && !key.intersection(range).isEmpty()) {
throw new IllegalArgumentException(
"Overlapping ranges: range " + range + " overlaps with entry " + entry)
}
}
}
keyRanges.add(range)
rangeMap.put(range, value)
this
}
def putAll(rangeMap: RangeMap[K, _ <: V]): SerializableBuilder[K, V] = {
for (entry <- JavaConversions.asScalaSet(rangeMap.asMapOfRanges().entrySet())) {
put(entry.getKey(), entry.getValue())
}
this
}
def build(): SerializableImmutableRangeMap[K, V] ={
val map: java.util.Map[Range[K], V] = rangeMap.asMapOfRanges()
val rangesBuilder: ImmutableList.Builder[Range[K]] = new ImmutableList.Builder[Range[K]](map.size())
val valuesBuilder: ImmutableList.Builder[V] = new ImmutableList.Builder[V](map.size())
for (entry: Entry[Range[K], V] <- JavaConversions.asScalaSet(map.entrySet())) {
rangesBuilder.add(entry.getKey())
valuesBuilder.add(entry.getValue())
}
return new SerializableImmutableRangeMap[K, V](rangesBuilder.build(), valuesBuilder.build())
}
}
def builder[K <: Comparable[_], V](): SerializableBuilder[K, V] = {
new SerializableBuilder[K, V]()
}
}
class SerializableImmutableRangeMap[K <: Comparable[_], V](ranges: ImmutableList[Range[K]], values: ImmutableList[V]) extends ImmutableRangeMap[K, V](ranges, values) with Serializable {
def this() {
this(ImmutableList.of(), ImmutableList.of())
}
}
堆栈跟踪：
java.io.InvalidClassException: com.google.common.collect.SerializableImmutableRangeMap; no valid constructor
at java.io.ObjectStreamClass$ExceptionInfo.newInvalidClassException(ObjectStreamClass.java:150)
at java.io.ObjectStreamClass.checkDeserialize(ObjectStreamClass.java:768)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1775)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1707)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1345)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371)
at scala.collection.immutable.$colon$colon.readObject(List.scala:362)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1896)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1993)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1918)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371)
at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:68)
at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:94)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:60)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:41)
at org.apache.spark.scheduler.Task.run(Task.scala:64)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:203)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
答案 0 :(得分：8)
Serializable文档的相关位：
为了允许序列化非可序列化类的子类型，子类型可以承担保存和恢复超类型的公共，受保护和（如果可访问）包字段的状态的责任。只有当它扩展的类具有可访问的no-arg构造函数来初始化类的状态时，子类型才可以承担此责任。如果不是这种情况，则声明类Serializable是错误的。将在运行时检测到错误。
您的超类（ImmutableRangeMap）没有no-arg构造函数，而不是Serializable。这就是问题。没有要求为Serializable类（例如SerializableImmutableRangeMap）设置no-arg构造函数。