spring-boot：使用JPA访问数据源（二）实现where条件，order by查询

上一篇文章：spring-boot：使用JPA访问数据源（一）

一、使用where条件

上一篇我们使用JPA进行了数据源的访问，默认JPA已经实现了好几个接口可以调用。但是，在实际的业务中，查询语句不可避免地需要使用where、order by等语句。

我们用商品数据来做例子，添加一个价格字段price，按价格范围查询，看看怎么来实现。

方式一：通过方法名称来实现

public interface GoodsRepository extends JpaRepository {
	List findByPriceBetween(Double startPrice, Double endPrice);
}

Spring Data JPA 查询方法支持的关键字（可参考：https://docs.spring.io/spring-data/jpa/docs/2.2.x/reference/html/#repositories.query-methods）

Table 2.2. Supported keywords inside method names

Keyword	Sample	JPQL snippet
And	findByLastnameAndFirstname	… where x.lastname = ?1 and x.firstname = ?2
Or	findByLastnameOrFirstname	… where x.lastname = ?1 or x.firstname = ?2
Between	findByStartDateBetween	… where x.startDate between 1? and ?2
LessThan	findByAgeLessThan	… where x.age < ?1
GreaterThan	findByAgeGreaterThan	… 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 ages)	… where x.age in ?1
NotIn	findByAgeNotIn(Collection age)	… where x.age not in ?1
True	findByActiveTrue()	… where x.active = true
False	findByActiveFalse()	… where x.active = false

 

方式二：通过自定义SQL来实现

在现实中，可能会含有非常复杂的SQL语句，或者为了性能优化，我们需要自定义sql。JPA提供注解和XML配置这2中方式。

public interface GoodsRepository extends JpaRepository {
	@Query(value = "select * from goods g where g.price between :startPrice and :endPrice", nativeQuery = true)
	List findByPriceBetween(Double startPrice, Double endPrice);
}

二、order by查询

使用order by也可以编写在方法名上，可以把以上例子改为

public interface GoodsRepository extends JpaRepository {
	List findByPriceBetweenOrderByPriceAsc(Double startPrice, Double endPrice);
}

至于自定义sql这里就省略了