Java流获取Spring Data JPA Onetomany Collection作为null

Question

public class ValidateClaimDataEntity{
    ...
    @OneToMany(mappedBy = "claimDataEntity")
    private List<ValidateEventDataEntity> eventDataEntityList;
}

当我做

时

function(ValidateClaimDataEntity claimDataEntity){
   claimDataEntity
            .getEventDataEntityList().parallelStream()....
}

我有零点例外 .getEventDataentityList((为null但是实际上，这种索赔范围具有DB

中相关的事件数据

我以ut的方式做：

claimDataEntityRepository.findById(32L).get().getEventDataEntityList().parallelStream().forEach(eventDataEntity -> {
            log.info(eventDataEntity.getValidateEventDataId());
        });

它进行日志事件数据

所以，为什么函数索赔符号将eventlist作为null ???

获取eventlist。

----------------------------------------------------------------------------------------------------------------------------------------------------------------------

我发现这可能不是流的问题，实际上，我在迭代器之前保存

public ValidateClaimResponse bc(ValidateClaimRequest claimRequest) {
        //claim
        ValidateClaimDataEntity claimDataEntity = new ValidateClaimDataEntity(claimRequest);
        claimDataEntityRepository.save(claimDataEntity);
        claimRequest.getEventRequestList()
                .forEach(eventRequest -> {
                    ...
                    //event
                    ValidateEventDataEntity eventDataEntity = new ValidateEventDataEntity(eventRequest);
                    eventDataEntity.setValidateClaimDataId(claimDataEntity.getValidateClaimDataId());
                    eventDataEntityRepository.save(eventDataEntity);
                });

    System.out.println(claimDataEntity.getEventDataEntityList() == null ? "null" : claimDataEntity.getEventDataEntityList() );
    ValidateClaimDataEntity claimDataEntity2 = claimDataEntityRepository.findById(claimDataEntity.getValidateClaimDataId()).get();
    System.out.println(claimDataEntity2.getEventDataEntityList() == null ? "null2" : claimDataEntity2.getEventDataEntityList());

我都得到了eventlist的null

Answer 1

@OneToMany的默认fetchType是懒惰的(一对一的默认fetch type类型，多对一，一对一，在冬眠中一对一(。因此，它没有被取出。使其EAGER

@OneToMany(mappedBy = "claimDataEntity", fetch = FetchType.EAGER)
private List<ValidateEventDataEntity> eventDataEntityList;