[英]oracle.sql.TIMESTAMP cannot be cast to java.sql.Timestamp
[英]Kryo cannot serialize a java.sql.Timestamp?
編輯:使用Kryo 1.04
我現在正在序列化一個Scala中包含java.sql.Timestamp
字段的User
類。 由於某些原因,Kryo無法找到零參數構造函數並引發錯誤:
Caused by: com.esotericsoftware.kryo.SerializationException: Class cannot be created (missing no-arg constructor): java.sql.Timestamp
Serialization trace:
created (com.threetierlogic.AccountService.models.User)
at com.esotericsoftware.kryo.Kryo.newInstance(Kryo.java:688)
at com.esotericsoftware.kryo.Serializer.newInstance(Serializer.java:75)
at com.esotericsoftware.kryo.serialize.FieldSerializer.readObjectData(FieldSerializer.java:200)
at com.esotericsoftware.kryo.serialize.FieldSerializer.readObjectData(FieldSerializer.java:220)
at com.esotericsoftware.kryo.serialize.FieldSerializer.readObjectData(FieldSerializer.java:200)
at com.esotericsoftware.kryo.Serializer.readObject(Serializer.java:61)
at com.esotericsoftware.kryo.Kryo.readObject(Kryo.java:589)
... 84 more
Caused by: java.lang.InstantiationException: java.sql.Timestamp
at java.lang.Class.newInstance0(Class.java:340)
at java.lang.Class.newInstance(Class.java:308)
at com.esotericsoftware.kryo.Kryo.newInstance(Kryo.java:676)
... 90 more
這是為Riak轉換域對象的轉換器類的一部分。 這是我的轉換器類:
/**
* Kryo converter for passing domain objects into Riak
*/
class UserConverter(val bucket: String) extends Converter[User] {
def fromDomain(domainObject: User, vclock: VClock): IRiakObject = {
val key = domainObject.guid
if(key == null) throw new NoKeySpecifedException(domainObject)
val kryo = new Kryo()
kryo.register(classOf[User])
kryo.register(classOf[Timestamp])
val ob = new ObjectBuffer(kryo)
val value = ob.writeObject(domainObject)
RiakObjectBuilder.newBuilder(bucket, key)
.withValue(value)
.withVClock(vclock)
.withContentType(Constants.CTYPE_OCTET_STREAM)
.build()
}
def toDomain(riakObject: IRiakObject): User = {
if(riakObject == null) null
val kryo = new Kryo()
kryo.register(classOf[User])
kryo.register(classOf[Timestamp])
val ob = new ObjectBuffer(kryo)
ob.readObject(riakObject.getValue(), classOf[User])
}
}
我是否需要擴展Timestamp並創建零參數構造函數? 還是有更好的解決方法?
如果我需要升級到2.20,那么在不寫入文件的情況下ObjectBuffer
的替代品是什么?
您可以執行以下操作:
class KryoSO {
import com.esotericsoftware.kryo.KryoSerializable
import de.javakaffee.kryoserializers.KryoReflectionFactorySupport
import com.esotericsoftware.kryo.Kryo
import com.esotericsoftware.kryo.Serializer
import java.io.{ InputStream, OutputStream }
import com.esotericsoftware.kryo.io.{ Output, Input }
import java.sql.Timestamp
object TimestampSerializer extends Serializer[Timestamp] {
override def write(kryo: Kryo, output: Output, t: Timestamp): Unit = {
output.writeLong(t.getTime(), true);
}
override def read(kryo: Kryo, input: Input, t: Class[Timestamp]): Timestamp = {
new Timestamp(input.readLong(true));
}
override def copy(kryo: Kryo, original: Timestamp): Timestamp = {
new Timestamp(original.getTime());
}
}
val kryo: Kryo = new KryoReflectionFactorySupport
kryo.addDefaultSerializer(classOf[Timestamp], TimestampSerializer)
def serialize(o: Any, os: OutputStream) = {
val output = new Output(os);
this.kryo.writeClassAndObject(output, o);
output.flush();
}
def deserialize(is: InputStream): Any = {
kryo.readClassAndObject(new Input(is));
}
}
val k = new KryoSO
val b = new java.io.ByteArrayOutputStream
val timestamp = new java.sql.Timestamp(System.currentTimeMillis())
k.serialize(timestamp, b)
val result = k.deserialize(new java.io.ByteArrayInputStream(b.toByteArray()))
println(timestamp)
println(result.getClass)
println(result.isInstanceOf[java.sql.Timestamp])
println(timestamp == result)
結果:
2013-02-07 10:59:19.482
class java.sql.Timestamp
true
true
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