Spring webflux 和 spring boot starter graphql 不返回可为 null 的字段

Question

我使用以下依赖项使用graphql创建了spring web Flux

 <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-graphql</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.graphql</groupId>
        <artifactId>spring-graphql-test</artifactId>
        <scope>test</scope>
    </dependency>

和我的 graphql 端点t

@Controller
public class UserController {
private final UserService userService;


public UserController(UserService userService) {
    this.userService = userService;
}

@SneakyThrows
@QueryMapping
public Flux<User> getUser() {
    return userService.findAllUsers();
}

和用户对象

public class User extends ReusableField implements Serializable {

private static final long serialVersionUID = 1L;

@Id
private Long id;
private String email;

private String fieldNullable;
....

字段 fieldNullable 未从 graphql 响应返回，因此 apollo-garaphql 对于角度显示控制台错误“写入结果时缺少字段 'fieldNullable'”

如何让spring返回这个字段，无论它是否为空

Answer 1

我发现了问题。我有一个 bean 定义

@Bean
public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {
    MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter();
    ObjectMapper mapper = new ObjectMapper();

    mapper.registerModule(new ParameterNamesModule())
            .registerModule(new Jdk8Module())
            .registerModule(new JavaTimeModule());

    mapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    jsonConverter.setObjectMapper(mapper);
    return jsonConverter;
}

问题出在这一行

mapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);

更改为

mapper.setSerializationInclusion(JsonInclude.Include.USE_DEFAULTS);

问题解决了`