Spring Boot MongoDB聚合管道线找不到类型的属性

Question

我有一个称为“约会”的文档集合，我正在尝试将每天的约会数量分组在一起，并填充一个称为AppointmentSummary的对象列表，其中每天将有一个对象，我正在使用Spring boot尝试并实现这一点，但是我一直遇到问题。

我在同一包中创建了以下三个类

AppointmentSummaryRepository.java

public interface AppointmentSummaryRepository extends
MongoRepository<Appointment,String>, AppointmentSummaryRepositoryCustom {

}

AppointmentSummaryRepositoryCustom.java

public interface AppointmentSummaryRepositoryCustom {

List<AppointmentSummary> aggregate(LocalDate startDate, LocalDate endDate);

}

AppointmentSummaryRepositoryImpl.java

public class AppointmentSummaryRepositoryImpl implements    AppointmentSummaryRepositoryCustom {

    private final MongoTemplate mongoTemplate;

    private final Logger log = LoggerFactory.getLogger(AppointmentSummaryRepositoryImpl.class);


    @Autowired
    public AppointmentSummaryRepositoryImpl(MongoTemplate mongoTemplate){
        this.mongoTemplate = mongoTemplate;
    }


    @Override
    public List<AppointmentSummary> aggregate(LocalDate startDate, LocalDate endDate){
        log.debug("This is a request to aggerate appointment summary between {} to {}", startDate.toString(), endDate.toString());
        MatchOperation matchOperation = getMatchOperation(startDate, endDate);
        GroupOperation groupOperation = getGroupOperation();
        log.debug("End group operaton");
        ProjectionOperation projectionOperation = getProjectOperation();

        return mongoTemplate.aggregate(Aggregation.newAggregation(
                matchOperation,
                groupOperation,
                projectionOperation
        ), Appointment.class, AppointmentSummary.class).getMappedResults();


    }

    private MatchOperation getMatchOperation(LocalDate startDate, LocalDate endDate) {
        log.debug("Begin Match Operation");
        Criteria appointmentCriteria = where("appointment_date").gt(startDate).andOperator(where("appointment_date").lt(endDate));
        log.debug("End Match Operation");
        return match(appointmentCriteria);
    }


    private GroupOperation getGroupOperation() {
        log.debug("Performing Group Operation");
        return group("appointment_date")
                .last("appointment_date").as("appointment_date")
                .addToSet("id").as("appointmentIds")
                .sum("id").as("count");
    }



    private ProjectionOperation getProjectOperation() {
        log.debug("Begin project operation");
        return project("appointment_date","appointmentIds","count")
                .and("appointment_date").previousOperation();
    }

每当我运行它时，都会不断出现以下错误：

org.springframework.data.mapping.PropertyReferenceException：找不到类型约会的属性约会！

我相信问题发生在以下代码段中，我的理解是，我初始化了管道的不同阶段，并将它们传递给mongoTemplate，“ getMappedResults”将映射两个对象中的字段并填充AppointmentSummary.class与聚合管道的输出？

return mongoTemplate.aggregate(Aggregation.newAggregation(
                matchOperation,
                groupOperation,
                projectionOperation
        ), Appointment.class, AppointmentSummary.class).getMappedResults();

注意，对象约会没有字段/属性约会。我在其中添加了代码，但是在运行代码时，我收到另一条错误消息，抱怨找不到约会的类型日期。

在此先感谢您的帮助！

Answer 1

下面使用模板蒙哥变种aggregate这需要collection name代替class。

mongoTemplate.aggregate(Aggregation.newAggregation(
            matchOperation,
            groupOperation,
            projectionOperation
    ), "appointment", AppointmentSummary.class).getMappedResults();

原因是，当您使用类型化的变体时，spring会对聚合管道中使用的字段运行验证以匹配pojo中的字段名称，并且在找不到别名时失败。