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 { @Column private String equipmentId; @Enumerated(EnumType.STRING) @Column(name = "equipment_type") private EquipmentType equipmentType; } ``` 2. equipmentType属性为枚举类,有TypeA和TypeB两个实例 3. 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); } ``` 4. 另外有实体类node类声明,Node表中equipmentId列与Equipment表中equipmentId列为逻辑外键关系,非物理外键 ``` @Entity @Table(name = "node") public class Node implements Serializable { @Column private String nodeNum; @Column private String equipmentId; } ``` 5. 实现基于springData JPA的查询方法,查询node表与 Equipment表中所有equipmentId相等的行,equipmentType的getInjectEquipmentType()方法返回为Optional的isPresent()方法返回值为true的记录的,并且nodeNum等于“aa”的记录 6. 基于@Query注解实现
时间: 2024-04-14 19:30:17 浏览: 65
要实现基于`springData JPA`的查询方法,查询`node`表与`Equipment`表中所有`equipmentId`相等的行,且`equipmentType`的`getInjectEquipmentType()`方法返回为`Optional`的`isPresent()`方法返回值为`true`的记录,并且`nodeNum`等于"aa"的记录,您可以使用`@Query`注解和JPQL(Java Persistence Query Language)来自定义查询语句。请按照以下步骤进行操作:
首先,在`Node`实体类中添加一个自定义查询方法,使用`@Query`注解指定JPQL查询语句,查询满足条件的记录:
```java
@Repository
public interface NodeRepository extends JpaRepository<Node, Long> {
@Query("SELECT n FROM Node n INNER JOIN Equipment e ON n.equipmentId = e.equipmentId WHERE n.nodeNum = 'aa' AND e.equipmentType.getInjectEquipmentType().isPresent() = true")
List<Node> findNodesWithInjectEquipmentTypeAndMatchingEquipmentId();
}
```
在上述代码中,`findNodesWithInjectEquipmentTypeAndMatchingEquipmentId()`方法使用了`@Query`注解来指定JPQL查询语句。该语句使用了内连接(INNER JOIN)将`Node`表和`Equipment`表关联,根据条件查询满足以下条件的记录:`nodeNum`等于"aa",且关联的`Equipment`对象的`equipmentType`的`getInjectEquipmentType()`方法返回的`Optional`对象的`isPresent()`方法返回值为`true`。
然后,在您的服务类(例如,`NodeService`)中注入`NodeRepository`,并调用该方法来获取满足条件的记录:
```java
@Service
public class NodeService {
private final NodeRepository nodeRepository;
public NodeService(NodeRepository nodeRepository) {
this.nodeRepository = nodeRepository;
}
public List<Node> findNodesWithInjectEquipmentTypeAndMatchingEquipmentId() {
return nodeRepository.findNodesWithInjectEquipmentTypeAndMatchingEquipmentId();
}
}
```
通过这种方式,您可以使用`@Query`注解和JPQL来实现基于`springData JPA`的查询方法,查询`node`表与`Equipment`表中所有`equipmentId`相等的行,且`equipmentType`的`getInjectEquipmentType()`方法返回为`Optional`的`isPresent()`方法返回值为`true`的记录,并且`nodeNum`等于"aa"的记录。
阅读全文