I get java.lang.StackOverflowError
when trying to serialize Object
that contains java.nio.file.Path
Even when i wrote:
public class PathConverter implements JsonDeserializer<Path>, JsonSerializer<Path> {
@Override
public Path deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) throws JsonParseException {
return Paths.get(jsonElement.getAsString());
}
@Override
public JsonElement serialize(Path path, Type type, JsonSerializationContext jsonSerializationContext) {
return new JsonPrimitive(path.toString());
}
}
and apply it:
String json = new GsonBuilder()
.registerTypeAdapter(Path.class, new PathConverter())
.create()
.toJson(constructorSetup, new TypeToken<ConstructorSetup>() {}.getType());
I still can't serialize this class:
public class ConstructorSetup {
private Path appIconMimmapDirPathOnPc;
}
Stacktrace: (full on pastebin)
Exception in thread "main" java.lang.StackOverflowError
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:380)
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:375)
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:380)
...
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:380)
at com.google.gson.internal.$Gson$Types.resolve($Gson$Types.java:355)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:117)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
at com.google.gson.Gson.getAdapter(Gson.java:356)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.<init>(ReflectiveTypeAdapterFactory.java:82)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:81)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:118)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
at com.google.gson.Gson.getAdapter(Gson.java:356)
...
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.<init>(ReflectiveTypeAdapterFactory.java:82)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:81)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:118)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
at com.google.gson.Gson.getAdapter(Gson.java:356)
Any solution?
Your problem is that Path
is an interface
. Let's suppose you used Paths.get("/")
which will create instance of something like WindowsPath
on my Windows PC. Now, you have to tell GSON how to deserialize this type:
ConstructorSetup setup = new ConstructorSetup();
setup.setAppIconMimmapDirPathOnPc(Paths.get("/"));
// here we get actual class type of our Path object
Class classT = setup.getAppIconMimmapDirPathOnPc().getClass();
Gson gson = new GsonBuilder().registerTypeAdapter(classT, new MyPathConverter())
Another approach you can go with is to registerTypeHierarchyAdapter
:
.registerTypeHierarchyAdapter(Path.class, new MyPathConverter())
The purpose of typeHierarchyAdapter is to cover the case when you want the same representation for all subtypes of a type, which is exactly your case with Path
.