Gson:java.lang.StackOverflower错误:null
我有一个类Delete,我想使用Gson库将其转换为json,但当我转换它时,它抛出异常Gson:java.lang.StackOverflower错误:null,java,json,scala,serialization,gson,Java,Json,Scala,Serialization,Gson,我有一个类Delete,我想使用Gson库将其转换为json,但当我转换它时,它抛出异常java.lang.StackOverflowerError:null 这是我的班级 import models.UserNotifications.MailMessages.DeleteReason._ import models.UserNotifications.MailMessages.DeleteStatus._ @SerialVersionUID(1) class Delete extends
java.lang.StackOverflowerError:null
这是我的班级
import models.UserNotifications.MailMessages.DeleteReason._
import models.UserNotifications.MailMessages.DeleteStatus._
@SerialVersionUID(1)
class Delete extends Serializable {
var deleteStatus : DeleteStatus = DELETED
var deleteReason : DeleteReason = EXPIRED
/*
* Setters
*/
def setDeleteStatus(deletestatus : String)= {
deleteStatus = DeleteStatus.withName(deletestatus)
}
def setDeleteReason ( deletereason : String) ={
deleteReason = DeleteReason.withName(deletereason)
}
/*
* Getter
*/
def getDeleteStatus : DeleteStatus = {
deleteStatus
}
def getDeleteReason : DeleteReason = {
deleteReason
}
}
下面是枚举类
DeleteStatus.scala
object DeleteStatus extends Enumeration {
type DeleteStatus = Value
val DELETED, ACTIVE = Value
}
DeleteReason.scala
object DeleteReason extends Enumeration{
type DeleteReason = Value
val EXPIRED , MANUALLY_DELETED = Value
}
下面是我如何转换Json的
var delete = new Delete
val gson = new Gson();
val g=gson.toJson(delete)
但它抛出了以下异常
java.lang.StackOverflowError: null
at com.google.gson.reflect.TypeToken.equals(TypeToken.java:284) ~[gson-2.3.1.jar:na]
at java.util.HashMap.getNode(HashMap.java:571) ~[na:1.8.0_45]
at java.util.HashMap.get(HashMap.java:556) ~[na:1.8.0_45]
at java.util.Collections$SynchronizedMap.get(Collections.java:2584) ~[na:1.8.0_45]
at com.google.gson.Gson.getAdapter(Gson.java:335) ~[gson-2.3.1.jar:na]
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:55) ~[gson-2.3.1.jar:na]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:99) ~[gson-2.3.1.jar:na]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:219) ~[gson-2.3.1.jar:na]
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68) ~[gson-2.3.1.jar:na]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:99) ~[gson-2.3.1.jar:na]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:219) ~[gson-2.3.1.jar:na]
请说明错误所在问题在于Scala枚举的字节码包含可能值的集合,每个值都是枚举的实例 例如,如果我们在上运行
javap CoinFaces
:
object CoinFaces extends Enumeration {
type CoinFaces = Value
val Heads, Tails = Value
}
我们可以看到Java反汇编包含类型为枚举$Value
的静态字段值
:
public final class CoinFaces {
public static scala.Enumeration$Value Tails();
public static scala.Enumeration$Value Heads();
public static scala.Enumeration$ValueSet$ ValueSet();
public static scala.Enumeration$ValueOrdering$ ValueOrdering();
public static scala.Enumeration$Value withName(java.lang.String);
public static scala.Enumeration$Value apply(int);
public static int maxId();
public static scala.Enumeration$ValueSet values();
public static java.lang.String toString();
}
这意味着在Java中,所有Scala枚举都包含循环引用。对此,最简单的解决方案是注释诸如@transient
()之类的字段。不幸的是,由于我们无法为自定义Scala枚举
注释生成的字节码,因此解决方案是创建一个自定义GSON序列化程序,手动将枚举值序列化为字符串
import com.google.gson.JsonElement;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import scala.Enumeration;
import java.lang.reflect.Type;
// Scala enumerations are static Java classes with values of type `Enumeration.Value`
public class GsonScalaEnumerationSerializer implements JsonSerializer<Enumeration.Value> {
@Override
public JsonElement serialize(final Enumeration.Value enumValue,
final Type typeOfEnum,
final JsonSerializationContext context) {
return new JsonPrimitive(enumValue.toString());
}
}
Gson gson = new GsonBuilder()
.registerTypeAdapter(Enumeration.Value.class, new GsonScalaEnumerationSerializer())
.create();