Java 在JPARepository中获取聚合查询结果
我正在尝试从我的应用程序中的JPARepository获取聚合数据。SQL类比如下:Java 在JPARepository中获取聚合查询结果,java,spring,jpa,Java,Spring,Jpa,我正在尝试从我的应用程序中的JPARepository获取聚合数据。SQL类比如下: SELECT c.sex as Sex, count(c.sex) as Count FROM customer c GROUP BY c.sex 该实体为: @Entity(name = "customer") public class Customer { @Id @GeneratedValue(strategy = GenerationType.AUTO) private L
SELECT c.sex as Sex, count(c.sex) as Count
FROM customer c
GROUP BY c.sex
该实体为:
@Entity(name = "customer")
public class Customer {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private Person.Sex sex;
...
}
我的假设是:
public interface CustomerRepository extends JpaRepository<Customer, Long> {
@Query(value = "SELECT c.sex as Sex, count(c.sex) as Count FROM customer c")
List<Object[]> countBySex();
}
公共接口CustomerRepository扩展了JpaRepository{
@查询(value=“选择c.sex作为性别,将(c.sex)作为客户c的计数”)
List countBySex();
}
SQL方法不返回任何结果,为什么不返回,还有非SQL方法吗
我使用的是Spring1.4.0.RELEASE
提前谢谢
编辑:当我为JPA添加persistence.xml配置以及相关类(Customer.class)的映射时,SQL方法起了作用。要从域或表中获取自定义记录,我们需要遵循其他方法。 我们可以使用jdbcTemplate获得结果,并使用行映射器类将其与dto绑定
有关更多详细信息,请浏览当我为JPA添加persistence.xml配置并映射相关类(Customer.class)时,SQL方法起到了作用。否则,应用程序无法从查询中识别表“Customer” persistence.xml代码如下所示:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="jpa.sample.plain">
<class>net.datamanager.application.Customer</class>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect" />
<property name="hibernate.connection.url" value="jdbc:hsqldb:mem:spring" />
<property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver" />
<property name="hibernate.connection.username" value="sa" />
<property name="hibernate.connection.password" value="" />
<property name="hibernate.hbm2ddl.auto" value="create-drop" />
</properties>
</persistence-unit>
net.datamanager.application.Customer