Custom Object Mapper

Pulsar uses an internal Jackson ObjectMapper when de/serializing JSON messages. If you instead want to provide your own object mapper instance, you can register a SchemaResolverCustomizer and set your mapper on the DefaultSchemaResolver as follows:

@Bean
SchemaResolverCustomizer<DefaultSchemaResolver> schemaResolverCustomizer() {
    return (DefaultSchemaResolver schemaResolver) -> {
        var myObjectMapper = obtainMyObjectMapper();
        schemaResolver.setObjectMapper(myObjectMapper);
    };
}

This results in your object mapper being used to de/serialize all JSON messages that go through the schema resolution process (i.e. in cases where you do not pass a schema in directly when producing/consuming messages).

Under the hood, the resolver creates a special JSON schema which leverages the custom mapper and is used as the schema for all resolved JSON messages.

If you need to pass schema instances directly you can use the JSONSchemaUtil to create schemas that respect the custom mapper. The following example shows how to do this when sending a message with the PulsarTemplate variant that takes a schema parameter:

void sendMessage(PulsarTemplate<MyPojo> template, MyPojo toSend) {
    var myObjectMapper = obtainMyObjectMapper();
    var schema = JSONSchemaUtil.schemaForTypeWithObjectMapper(MyPojo.class, myObjectMapper);
    template.send(toSend, schema);
}

Pulsar configures its default object mapper in a particular way. Unless you have a specific reason to not do so, it is highly recommended that you configure your mapper with these same options as follows:

myObjectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
myObjectMapper.configure(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_AS_NULL, false);
myObjectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

A later version of the framework may instead provide a customizer that operates on the default mapper rather than requiring a separate instance.