1. 现有基于JPA标准映射的数据库实体类声明如下: ```java @Entity @Table(name = "equipment") public class Equipment implements Serializable { @Enumerated(EnumType.STRING) @Column(name = "equipment_type") private EquipmentType equipmentType; } ``` 2. equipmentType属性为枚举类,每个枚举类有getInjectEquipmentType()方法,方法签名如下 ```java @Override public Optional<InjectEquipmentType> getInjectEquipmentType() { return Optional.of(InjectEquipmentType.BEAR_USW_STATION); } ``` 3. 实现基于springData JPA的查询方法,查询Equipment表中所有equipmentType的getInjectEquipmentType()方法返回为Optional的isPresent()方法返回值为true的记录的总数
时间: 2024-04-13 21:30:40 浏览: 8
要查询`Equipment`表中所有`equipmentType`的`getInjectEquipmentType()`方法返回为`Optional`的`isPresent()`方法返回值为`true`的记录的总数,您可以使用Spring Data JPA的命名规则自定义查询方法。请按照以下步骤进行操作:
首先,在`Equipment`实体类中添加一个自定义查询方法,使用Spring Data JPA的命名规则来定义查询逻辑:
```java
@Repository
public interface EquipmentRepository extends JpaRepository<Equipment, Long> {
int countByEquipmentTypeGetInjectEquipmentTypeIsPresentTrue();
}
```
在上述代码中,`countByEquipmentTypeGetInjectEquipmentTypeIsPresentTrue()`方法使用了Spring Data JPA的命名规则来定义查询逻辑。根据命名规则,Spring Data JPA会自动生成查询语句,查询`Equipment`表中所有满足条件的记录并返回其总数。
然后,在您的服务类(例如,`EquipmentService`)中注入`EquipmentRepository`,并调用该方法来获取满足条件的记录的总数:
```java
@Service
public class EquipmentService {
private final EquipmentRepository equipmentRepository;
public EquipmentService(EquipmentRepository equipmentRepository) {
this.equipmentRepository = equipmentRepository;
}
public int countEquipmentsWithInjectEquipmentType() {
return equipmentRepository.countByEquipmentTypeGetInjectEquipmentTypeIsPresentTrue();
}
}
```
在上述代码中,`countEquipmentsWithInjectEquipmentType()`方法调用了`countByEquipmentTypeGetInjectEquipmentTypeIsPresentTrue()`方法来获取满足条件的记录的总数。
通过这种方式,您可以使用Spring Data JPA和基于命名规则的查询方法来查询`Equipment`表中所有`equipmentType`的`getInjectEquipmentType()`方法返回为`Optional`的`isPresent()`方法返回值为`true`的记录的总数。