Java 类com.fasterxml.jackson.databind.ser.std.NullSerializer 实例源码

private SchemaAware getValueSerializer(Object valueAsJavaType) throws JsonMappingException {

        SerializerProvider serializerProvider = new DefaultSerializerProvider.Impl().createInstance(OBJECT_MAPPER.getSerializationConfig(), BeanSerializerFactory.instance);

        if (valueAsJavaType == null) {
            return NullSerializer.instance;
        } else {
            Class<? extends Object> javaTypeForValue = valueAsJavaType.getClass();
            JsonSerializer<Object> valueSerializer = serializerProvider.findValueSerializer(javaTypeForValue, null);
            return (SchemaAware) valueSerializer;
        }
    }

public CustomObjectMapper() {
    DefaultSerializerProvider sp = new DefaultSerializerProvider.Impl();
    sp.setNullValueSerializer(NullSerializer.instance);
    this.setSerializerProvider(sp);
}

public final JsonSerializer<?> getNullSerializer()
{
  return NullSerializer.instance;
}