jackson-patterns

// ✅ Spring Boot 配置(ObjectMapper全局)
@Configuration
public class JacksonConfig {
    @Bean
    public Jackson2ObjectMapperBuilderCustomizer customizer() {
        return builder -> builder
            .simpleDateFormat("yyyy-MM-dd HH:mm:ss")
            .serializationInclusion(JsonInclude.Include.NON_NULL)
            .featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
            .featuresToEnable(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES);
    }
}

// ✅ 注解方式
@Data
public class UserVO {
    @JsonProperty("user_name")   // JSON字段重命名
    private String username;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private LocalDateTime createTime;

    @JsonIgnore                  // 序列化时忽略
    private String password;

    @JsonView(Views.Detail.class) // 仅详情视图返回
    private String email;
}

// ✅ TypeReference 反序列化
List<User> users = objectMapper.readValue(json,
    new TypeReference<List<User>>(){});

// ✅ Null值处理规则
objectMapper.configOverride(String.class)
    .setInclude(JsonInclude.Value.construct(
        JsonInclude.Include.NON_NULL,  // null string → null
        JsonInclude.Include.NON_NULL
    ));