为什么 Spring Boot 不使用自定义 ObjectMapper bean？

Question

我有自定义 ObjectMapper bean 注释为 @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;
    }

}

但是，当我尝试使用不同大小写的枚举来解析表单时，它给了我错误。

@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;
    }

}

这里是 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()
}

我试图声明 Jackson2ObjectMapperBuilder bean。它没有帮助。
知道可能会发生什么，或者我应该在哪里寻找问题？

Answer 1

检查您是否让 spring boot 自动配置您的应用程序。在您的 Spring Boot 应用程序配置中，少即是多。如果你添加了@EnableWebMvc，你会阻止 spring boot 自动配置你的序列化和反序列化。

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

Answer 2

1. 创建一个Jackson2ObjectMapperBuilderCustomizer bean，例如。 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. 或者在spring boot应用属性中自定义。例如。 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