为什么 Spring 引导不使用自定义 ObjectMapper bean？

Question

I have custom ObjectMapper bean annotated as @Primary.

@Configuration
public class BeanConfig {

    @Bean
    @Primary
    public ObjectMapper objectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.registerModule(new Jdk8Module());
        objectMapper.enable(MapperFeature.ACCEPT_CASE_INSENSITIVE_ENUMS);
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_ABSENT);
        return objectMapper;
    }

}

However when I try to parse form with not same case written enum it gives me error.

@RestController
@RequestMapping("/game")
public class GameController {

    private final GameService gameService;

    public GameController(GameService gameService) {
        this.gameService = gameService;
    }

    @PostMapping("/create")
    public ResponseEntity<?> createGame(
            @AuthenticationPrincipal String id,
            GameParametersForm gameParametersForm
    ) {
        Result<String> result = gameService.createWebGameSession(id, gameParametersForm);
        return result.toResponseEntity();
    }

}

public class GameParametersForm {

    private Mode mode;

    public GameParametersForm(
            Mode mode
    ) {
        this.mode = mode;
    }

    public Mode getMode() {
        return mode;
    }

}

Here is build.gradle

plugins {
    id 'org.springframework.boot' version '2.4.3'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {
    mavenCentral()
    maven { url 'https://jitpack.io' }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.fasterxml.jackson.core:jackson-annotations:2.12.2'
    implementation 'com.fasterxml.jackson.core:jackson-databind:2.12.2'
    implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jdk8:2.12.2'
    implementation 'javax.validation:validation-api:2.0.1.Final'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-security'
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    implementation 'org.springframework.boot:spring-boot-starter-websocket'
    implementation 'org.springframework.boot:spring-boot-starter-mail'
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
    implementation 'org.springframework.security:spring-security-test'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

test {
    useJUnitPlatform()
}

I have tried to declare Jackson2ObjectMapperBuilder bean. It didn't help.
Any idea what might be happening, or where else I should be looking to track down the issue?

Answer 1

1. Create a Jackson2ObjectMapperBuilderCustomizer bean, eg. hantsy/spring-r2dbc-sample DemoApplication.java#L152

    @Bean public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() { return builder -> { builder.serializationInclusion(JsonInclude.Include.NON_EMPTY); builder.featuresToDisable( SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, SerializationFeature.FAIL_ON_EMPTY_BEANS, DeserializationFeature.FAIL_ON_IGNORED_PROPERTIES, DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES); builder.featuresToEnable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY); }; }

2. Or customize it in spring boot application properties. eg. hantsy/spring-webmvc-jwt-sample application.yml#L4

    spring: jackson: mapper: DEFAULT_VIEW_INCLUSION: true serialization: indent_output: true WRITE_DATES_AS_TIMESTAMPS: false deserialization: FAIL_ON_IGNORED_PROPERTIES: false FAIL_ON_UNKNOWN_PROPERTIES: false ACCEPT_SINGLE_VALUE_AS_ARRAY: true default-property-inclusion: non_empty

Answer 2

Check that your letting spring boot auto configure your application. Less is more in your spring boot application configuration. If you have added @EnableWebMvc you prevent spring boot from auto configuring your serialization and deserialization.

https://docs.spring.io/spring-boot/docs/current/reference/html/spring-boot-features.html#boot-features-spring-mvc-auto-configuration