1. @MappedSuperclass
@MappedSuperclass
public abstract class CucdCriteriaBase {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String showName;
@Enumerated(EnumType.STRING)
private CompareCondition compareCondition;
private String compareValue;
//getter、setter
}
@Entity
@Table(name = "cucd_criteria_inspection")
public class CucdCriteriaInspection extends CucdCriteriaBase {
private String type;
//getter、setter
}
@MappedSuperclass 声明的父类不会对应数据库中的表，只有子类会跟数据库中的表对应
2. @OneToMany
2.1. 级联删除
@Entity
@Table(name = "cucd_criteria")
public class CucdCriteria {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String deviceType;
private String company;
private String description;
@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "criteria_id")
private List<CucdCriteriaBackup> backups;
@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "criteria_id")
private List<CucdCriteriaMetrics> metrics;
//getter、setter
}
2.2. 使用中间表关联
@Entity
@Table(name = "cucd_criteria_part")
public class CucdCriteriaPart {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@OneToMany
@JoinTable(name = "cucd_criteria_part_backup", joinColumns = @JoinColumn(name = "part_id"), inverseJoinColumns = @JoinColumn(name = "backup_id"))
private List<CucdCriteriaBackup> backups;
@OneToMany
@JoinTable(name = "cucd_criteria_part_metrics", joinColumns = @JoinColumn(name = "part_id"), inverseJoinColumns = @JoinColumn(name = "metrics_id"))
private List<CucdCriteriaMetrics> metrics;
//getter、setter
}
3. @ElementCollection
两个实体存在一对多关系且多的实体完全属于一的实体时使用，用DDD术语描述就是两个实体属于一个Aggregate并且一的实体是Aggregate Root
@Entity
@Table(name = "cucd_formula")
public class CucdFormula {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
@ElementCollection
@CollectionTable(name = "cucd_formula_device_name", joinColumns = @JoinColumn(name = "formula_id"))
@Column(name = "device_name")
private Set<String> deviceNames;
@ElementCollection
@CollectionTable(name = "cucd_formula_notify_type", joinColumns = @JoinColumn(name = "formula_id"))
@Enumerated(EnumType.STRING)
@Column(name = "notify_type")
private Set<NotifyType> notifyTypes; (1)
@ElementCollection
@CollectionTable(name = "cucd_formula_notifier", joinColumns = @JoinColumn(name = "formula_id"))
private Set<Notifier> notifiers; (2)
//getter、setter
@Embeddable
public static class Notifier {
private Integer userId;
private Integer orgId;
//getter、setter
}
}
-
cucd_formula_notify_type表有两列formula_id和notify_type -
cucd_formula_notifier表有三列formula_id、user_id和org_id
使用Criteria API根据 @ElementCollection 声明的属性进行模糊查询
public class CucdFormulaService {
public Page<CucdFormula> list(CucdFormula cucdFormula, Pageable pageable, String deviceName) {
Specification<CucdFormula> specification = (root, query, criteriaBuilder) -> {
List<Predicate> predicates = new ArrayList<>();
if (StringUtils.hasText(cucdFormula.getName())) {
predicates.add(criteriaBuilder.like(root.get(CucdFormula_.NAME), "%" + cucdFormula.getName() + "%"));
}
if (StringUtils.hasText(deviceName)) {
Subquery<Long> subquery = criteriaBuilder.createQuery(CucdFormula.class).subquery(Long.class);
Root<CucdFormula> subRoot = subquery.from(CucdFormula.class);
subquery.select(criteriaBuilder.literal(1L))
.where(criteriaBuilder.equal(root.get(CucdFormula_.ID), subRoot.get(CucdFormula_.ID)),
criteriaBuilder.like(subRoot.join(CucdFormula_.DEVICE_NAMES), "%" + deviceName + "%"));
predicates.add(criteriaBuilder.exists(subquery));
}
return criteriaBuilder.and(predicates.toArray(new Predicate[0]));
};
return cucdFormulaRepository.findAll(specification, pageable);
}
}
4. 预期外的持久化
问题描述：有如下的 OrderService 以及对应的 OrderController，从 OrderController 调用 orderService.feedback() 方法时参数 orderFeedbackRequest.getProcessTime() 为 null，因此 LocalDateTime.parse 抛出 NullPointerException 进行 catch 块执行，很明显因为发生了异常导致 orderSendRecordRepository.save(orderSendRecord); 没有执行，但最终数据库中 orderSendRecord 的 status 和 handler 仍然被修改
问题原因：项目保留了spring boot默认的 spring.jpa.open-in-view=true 的配置，因此 EntityManager 或者叫持久化上下文在整个请求期间都是打开的，因此 orderSendRecord 从未变成游离态，执行过 setStatus 和 setHandler 之后 orderSendRecord 就变脏，最终执行 orderLogRepository.save(orderLog); 时刷新持久化上下文也将变脏的 orderSendRecord 更新到数据库
orderLogRepository.save(orderLog); 会开启事务，事务提交时会调用 entityManager.flush()
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@Service
public class OrderService {
private final Logger logger = LoggerFactory.getLogger(OrderService.class);
private final OrderSendRecordRepository orderSendRecordRepository;
private final OrderLogRepository orderLogRepository;
public OrderService( OrderSendRecordRepository orderSendRecordRepository, OrderLogRepository orderLogRepository) {
this.orderSendRecordRepository = orderSendRecordRepository;
this.orderLogRepository = orderLogRepository;
}
public OrderFeedbackResponse feedback(OrderFeedbackRequest orderFeedbackRequest) {
String workOrderNo = orderFeedbackRequest.getWorkOrderNo();
Optional<OrderSendRecord> orderSendRecordOptional = orderSendRecordRepository.findByBusinessId(workOrderNo);
if (!orderSendRecordOptional.isPresent()) {
return OrderFeedbackResponse.failResponse("工单不存在");
}
OrderSendRecord orderSendRecord = orderSendRecordOptional.get();
try {
if(OrderSendRecordStatus.TO_HANDLE.equals(orderSendRecord.getStatus())) {
orderSendRecord.setStatus(OrderSendRecordStatus.HANDLED);
orderSendRecord.setHandler(orderFeedbackRequest.getProcessor());
orderSendRecord.setHandleTime(LocalDateTime.parse(orderFeedbackRequest.getProcessTime(), DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
orderSendRecord.setHandleRemark(orderFeedbackRequest.getProcessContent());
orderSendRecordRepository.save(orderSendRecord);
saveLog(orderSendRecord.getOrder().getId(), OrderLogType.HANDLE, orderFeedbackRequest.getProcessor(),true, "");
orderRepository.toComplete(orderSendRecord.getOrder().getId());
}
return OrderFeedbackResponse.successResponse();
} catch (Exception ex) {
logger.error("fail to feedback order, workOrderNo: " + workOrderNo, ex);
saveLog(orderSendRecord.getId(), OrderLogType.HANDLE, orderFeedbackRequest.getProcessor(),false, "");
return OrderFeedbackResponse.failResponse("回调失败");
}
}
private void saveLog(Long orderId, OrderLogType type, String operator, boolean success, String remark) {
OrderLog orderLog = new OrderLog();
orderLog.setOrderId(orderId);
orderLog.setType(type);
orderLog.setOperator(operator);
orderLog.setOperateTime(LocalDateTime.now());
orderLog.setResult(success ? "成功" : "失败");
orderLog.setRemark(remark);
orderLogRepository.save(orderLog);
}
}