Custom Jackson2ObjectMapperBuilder not recognized in an integration springboot test

Question

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I have customized Jackson2ObjectMapperBuilder in my main Spring Boot application class as below.

public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
}

@Autowired
public void configureJackson(Jackson2ObjectMapperBuilder builder) {
    builder.filters( new SimpleFilterProvider().addFilter( "customFilter", new ExampleFilter() ) );
}

where ExampleFilter is an extension of SimpleBeanPropertyFilter. My POJOs are annotated with Jackson's @JsonFilter("customFilter").
I have exposed the POJOs over HTTP using @RestController and @GetMapping annotations. This works fine and the custom filter gets invoked when I run the application and access the end point.

Now I have an integration test written as below.

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class IntegrationTest {

    @LocalServerPort
    private int port;

    @Autowired
    private TestRestTemplate restTemplate;

    @Test
    public void getUser() throws Exception {
        POJO obj = this.restTemplate.getForObject("http://localhost:" + this.port + "/pojo", POJO.class);

        Assertions.assertThat(obj).isNotNull();
        Assertions.assertThat(obj.getFirstName()).isEqualTo("Jane");
        Assertions.assertThat(obj.getLastName()).isEqualTo("Doe");
        Assertions.assertThat(obj.getAge()).isEqualTo("24");
    }
}

When I run the test, the obj comes as null and I see an error that no FilterProvider configured

Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: Can not resolve PropertyFilter with id 'customFilter'; no FilterProvider configured; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not resolve PropertyFilter with id 'customFilter'; no FilterProvider configured

What am I doing wrong and how do I correct this?

My folder structure is :
src/main/java/com/a/b/c/Application.java
src/main/java/com/a/b/c/controller/ControllerA.java

src/test/java/com/a/b/c/controller/IntegrationTest.java

Answer 1

I got this working by configuring Jackson2ObjectMapperBuilder in a slightly different way in the main application file as shown below. But I still don't know why the Autowiring approach isn't working.

@Bean
public Jackson2ObjectMapperBuilder objectMapperBuilder() {
    Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
    builder.filters( new SimpleFilterProvider().addFilter( "customFilter", new ExampleFilter() ) );
    return builder;
}

I'd still like to know that in the test context, why the auto configured Jackson2ObjectMapperBuilder isn't picked up for customization while replacing it with @Bean works.