Spring Data JPA根据属性名查询

一 点睛

Spring Data JPA支持通过定义在Repository接口的方法名来定义查询，而方法名是根据实体类的属性名来确定的。

二 常规查询

根据属性名来定义查询方法，示例如下：

public interface PersonRepo extends JpaRepository<Person,Long>{
    //相对于名字相等查询，参数为name
    List<Person> findByName(String name);
    //通过名字like查询，参数为name
    List<Person> findByNameLike(String name);
    //通过名字和地址查询，参数为name和address
    List<Person> findByNameAndAddress(String name,String address);
}

从代码可以看出，使用了findBy、Like，And这样的关键字，其中findBy可以用find、read、readBy、query、queryBy，get、getBy来代替。

三 限制结果数量

结果数量是用top和first关键字来实现的，示例如下：

public interface PersonRepo extends JpaRepository<Person,Long>{
    //查询符合查询条件的前10条数据
    List<Person> findFirst10ByName(String name);
    //获得符合查询条件的前30条数据
    List<Person> findTop30ByName(String name);
}

四 查询关键字列表

参考官网：https://docs.spring.io/spring-data/jpa/docs/2.0.9.RELEASE/reference/html/

关键字	示例	功能同JPQL
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	findByAgeIsNull	… 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)