Custom serailizers/ deserializers for ObjectMapping - json

Question

I have add multiple custom Serializers and Deserializers to my ObjectMapper. How to check if serializers are registered?
#Bean
public ObjectMapper getMyObjectMapper(List<TestSerializer> serializers, List<TestDeserializer> deserializers) {
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule customModule = new SimpleModule();
for (TestSerailizer h: serializers) {
customModule.addSerializer(h);
}
for (TestDeserializer d: deserializers) {
customModule.addDeserializer(Object.class, d);
}
objectMapper.registerModule(customModule);
objectMapper.registerModule(new JavaTimeModule());
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
return objectMapper;
}

Answer 1

You can invoke the ObjectMapper#getRegisteredModuleIds that returns the set of Module typeIds that are registered in the ObjectMapper mapper where by default the typeId for a module is it's full class name (see Module.getTypeId()):
ObjectMapper objectMapper = new ObjectMapper();
//it will print the modules registered
System.out.println(mapper.getRegisteredModuleIds());
If you are interested to check which serializer will be used for YourClass class, you can invoke the ObjectMapper#getSerializerProviderInstance returning a SerializerProvider instance that may be used for accessing serializers with the findValueSerializer method:
//it will print your serializer if you have defined one for your class
//otherwise one of the jackson java classes used for serialization
System.out.println(mapper.getSerializerProviderInstance()
.findValueSerializer(YourClass.class));