spring-data-jpa中的查詢方法
阿新 • • 發佈:2020-07-13
查詢方法,就是根據方法名來檢索資料。按照一定的規則,通過方法名描述要檢索的欄位,過濾的條件,排序的策略等等,它們大都以find
, get
... 等開頭。spring-data-jpa會自動解析,並且完成檢索。省時省力。
在 Repository 中定義查詢方法
public interface UserRepository extends Repository<User, Long> { // 根據emailAddress和lastname 檢索所有的記錄 List<User> findByEmailAddressAndLastname(String emailAddress, String lastname); }
這個方法最終執行的JPQL
select u from User u where u.emailAddress = ?1 and u.lastname = ?2
支援的語法
關鍵字 | 例如 | 最終執行的JPQL 片段 |
---|---|---|
And |
findByLastnameAndFirstname |
… where x.lastname = ?1 and x.firstname = ?2 |
Or |
findByLastnameOrFirstname |
… where x.lastname = ?1 or x.firstname = ?2 |
Is , Equals |
findByFirstname , findByFirstnameIs findByFirstnameEquals |
… where x.firstname = ?1 |
Between |
findByStartDateBetween |
… where x.startDate between ?1 and ?2 |
LessThan |
findByAgeLessThan |
… where x.age < ?1 |
LessThanEqual |
findByAgeLessThanEqual |
… where x.age <= ?1 |
GreaterThan |
findByAgeGreaterThan |
… where x.age > ?1 |
GreaterThanEqual |
findByAgeGreaterThanEqual |
… where x.age >= ?1 |
After |
findByStartDateAfter |
… where x.startDate > ?1 |
Before |
findByStartDateBefore |
… where x.startDate < ?1 |
IsNull , Null |
findByAge(Is)Null |
… where x.age is null |
IsNotNull , NotNull |
findByAge(Is)NotNull |
… where x.age not null |
Like |
findByFirstnameLike |
… where x.firstname like ?1 |
NotLike |
findByFirstnameNotLike |
… where x.firstname not like ?1 |
StartingWith |
findByFirstnameStartingWith |
… where x.firstname like ?1 (parameter bound with appended % ) |
EndingWith |
findByFirstnameEndingWith |
… where x.firstname like ?1 (parameter bound with prepended % ) |
Containing |
findByFirstnameContaining |
… where x.firstname like ?1 (parameter bound wrapped in % ) |
OrderBy |
findByAgeOrderByLastnameDesc |
… where x.age = ?1 order by x.lastname desc |
Not |
findByLastnameNot |
… where x.lastname <> ?1 |
In |
findByAgeIn(Collection<Age> ages) |
… where x.age in ?1 |
NotIn |
findByAgeNotIn(Collection<Age> ages) |
… where x.age not in ?1 |
True |
findByActiveTrue() |
… where x.active = true |
False |
findByActiveFalse() |
… where x.active = false |
IgnoreCase |
findByFirstnameIgnoreCase |
… where UPPER(x.firstame) = UPPER(?1) |
使用到
In
和NotIn
等對集合進行計算關鍵的字方法,支援使用Collection
子類,或者陣列作為引數的形參。
支援物件屬性導航
class User {
// User物件關聯了一個Address 物件
Address address;
}
class Address {
String name;
}
public interface UserRepositroy extends JpaRepository<User, Integer>{
// 從address屬性導航到它的name屬性
findByAddressName(String name);
// 更為科學的寫法, 通過下戶線標識遍歷的節點
findByAddress_Name(String name);
}
JPA裡面, 下戶線是保留識別符號,但是下劃線又破話了Java的駝峰規則
分頁和排序
只需要在方法的最後一個引數定義: Sort
/ Pageable
物件,即可自動的完成排序/分頁
Sort
和Pageable
是JPA定義用來排序和分頁的物件
也可以通過 First/Top 方法名限制結果集
findFirst10ByName(String name);
findTop10ByName(String name);
以上2個方法,都表示根據 name
屬性檢索前10條記錄
官方文件
這個花樣確實多,不過用到的就那麼幾個,有興趣,可以閱讀官方文件系統學習
https://docs.spring.io/spring-data/jpa/docs/current-SNAPSHOT/reference/html/#jpa.query-methods