@Query 与 @Modifying
1、@Query 注解
1.1、自定义查询
这种查询可以声明在 Repository 方法中，摆脱像命名查询那样的约束，将查询直接在相应的接口方法中声明，结构更为清晰，这是 Spring data 的特 有实现
@Query("SELECT C FROM Customer c WHERE c.customerId=?1")
Customer testGetByCustomerId2(Integer id);
复制代码测试方法
PersonRepository 类
@Query("select p from Person p where p.id=(select max(id) from Person p)")
Person getMaxIdPerson();
复制代码Test 类
@Test
public void testGetMaxIdPerson() {
Person person = repository.getMaxIdPerson();
System.out.println(person);
}
复制代码日志信息
Hibernate:
select
person0_.id as id1_1_,
person0_.add_id as add_id6_1_,
person0_.address_id as address_2_1_,
person0_.birth_day as birth_da3_1_,
person0_.email as email4_1_,
person0_.last_name as last_nam5_1_
from
jpa_persons person0_
where
person0_.id=(
select
max(person1_.id)
from
jpa_persons person1_
)
Person{id=27, lastName='XY', email='[email protected]', birthDay=2022-05-21 22:48:34.0}
复制代码结论：使用
@Query注解可以自定义 JPQL 语句以实现更灵活的查询
1.2、索引参数与命名参数
索引参数
索引参数如下所示，索引值从 1 开始，查询中 “?X” 个数需要与方法定义的参数个数相一致，并且顺序也要一致
@Modifying
@Query（"update User u set u.firstname=?1 where u.lastname=?2"）
int setFixedFirstnameFor(String firstname，String lastname);
复制代码命名参数
命名参数（推荐使用这种方式）：可以定义好参数名，赋值时采用 @Param("参数名")，而不用管顺序
@Query（"select cirom customer u where c.firstname=：firstname or c.lastname=：lastname"）
Customer findByLastnameOrFirstname(@Param("lastname") String lastname, @Param("firstname") String firstname);
复制代码测试方法 1
PersonRepository 类
@Query("select p from Person p where p.lastName=?1 and p.email=?2")
Person getByLastNameAndEmail(String lastName, String email);
复制代码Test 类
@Test
public void testGetByLastNameAndEmail() {
Person person = repository.getByLastNameAndEmail("AA", "[email protected]");
System.out.println(person);
}
复制代码日志信息
Hibernate:
select
person0_.id as id1_1_,
person0_.add_id as add_id6_1_,
person0_.address_id as address_2_1_,
person0_.birth_day as birth_da3_1_,
person0_.email as email4_1_,
person0_.last_name as last_nam5_1_
from
jpa_persons person0_
where
person0_.last_name=?
and person0_.email=?
Person{id=1, lastName='AA', email='[email protected]', birthDay=2022-05-21 22:48:34.0}
复制代码测试方法 2
PersonRepository 类
@Query("select p from Person p where p.lastName=:lastName and p.email=:email")
Person getByEmailAndLastName(@Param("email") String email, @Param("lastName") String lastName);
复制代码Test 类
@Test
public void testGetByEmailAndLastName() {
Person person = repository.getByEmailAndLastName("[email protected]", "BB");
System.out.println(person);
}
复制代码日志信息
Hibernate:
select
person0_.id as id1_1_,
person0_.add_id as add_id6_1_,
person0_.address_id as address_2_1_,
person0_.birth_day as birth_da3_1_,
person0_.email as email4_1_,
person0_.last_name as last_nam5_1_
from
jpa_persons person0_
where
person0_.last_name=?
and person0_.email=?
Person{id=2, lastName='BB', email='[email protected]', birthDay=2022-05-21 22:48:34.0}
复制代码1.3、模糊查询
如果是 @Query 中有 LIKE 关键字，后面的参数需要前面或者后面加 %，这样在传递参数值的时候就可以不加 %：
右模糊
@Query("select o from UserModel o where o.name like ?1%"）
public List<UserModel> findByUuidOrAge(String name);
复制代码左模糊
@Query("select o from UserModel o where o.name like %?1"）
public List<UserModel> findByUuidOrAge(String name);
复制代码全模糊
@Query("select o from UserModel o where o.name like %?1%"）
public List<UserModel> findByUuidOrAge(String name);
复制代码测试方法 1
PersonRepository 类
@Query("select p from Person p where p.lastName like %?1% or p.email like %?2%")
List<Person> findLikeLastNameOrEmail(String lastName, String email);
复制代码Test 类
@Test
public void testFindLikeLastNameOrEmail() {
List<Person> personList = repository.findLikeLastNameOrEmail("A", "BB");
System.out.println(personList);
}
复制代码日志信息
Hibernate:
select
person0_.id as id1_1_,
person0_.add_id as add_id6_1_,
person0_.address_id as address_2_1_,
person0_.birth_day as birth_da3_1_,
person0_.email as email4_1_,
person0_.last_name as last_nam5_1_
from
jpa_persons person0_
where
person0_.last_name like ?
or person0_.email like ?
[Person{id=1, lastName='AA', email='[email protected]', birthDay=2022-05-21 22:48:34.0}, Person{id=2, lastName='BB', email='[email protected]', birthDay=2022-05-21 22:48:34.0}]
复制代码测试方法 2
PersonRepository 类
@Query("select p from Person p where p.lastName like %:lastName% or p.email like %:email%")
List<Person> findLikeEmailOrLastName(@Param("email") String email, @Param("lastName") String lastName);
复制代码Test 类
@Test
public void testFindLikeEmailOrLastName() {
List<Person> personList = repository.findLikeEmailOrLastName("DD", "C");
System.out.println(personList);
}
复制代码日志信息
Hibernate:
select
person0_.id as id1_1_,
person0_.add_id as add_id6_1_,
person0_.address_id as address_2_1_,
person0_.birth_day as birth_da3_1_,
person0_.email as email4_1_,
person0_.last_name as last_nam5_1_
from
jpa_persons person0_
where
person0_.last_name like ?
or person0_.email like ?
[Person{id=3, lastName='CC', email='[email protected]', birthDay=2022-05-21 22:48:34.0}, Person{id=4, lastName='DD', email='[email protected]', birthDay=2022-05-21 22:48:34.0}]
复制代码1.4、本地查询
还可以使用 @Query 来指定本地查询，只要设置 nativeQuery 为 true，比如：
@Query(value="select * from tbl_user where name like %?1", nativeQuery=true)
public List<UserModel> findByUuidOrAge(String name);
复制代码测试方法
PersonRepository 类
@Query(value = "select count(1) FROM jpa_persons", nativeQuery = true)
int getTotalCount();
复制代码Test 类
@Test
public void testGetTotalCount() {
int totalCount = repository.getTotalCount();
System.out.println(totalCount);
}
复制代码日志信息
Hibernate:
select
count(1)
FROM
jpa_persons
27
复制代码2、@Modifying 注解
2.1、执行更新操作
@Query 与 @Modifying 这两个 annotation 一起声明，可定义个性化更新操作，例如只涉及某些字段更新时最为常用，示例如下：
@Modifying
@Query("UPDATE Customerg SET c.customerName=?1")
int updateCustomerName(String cn);
复制代码注意：
- 方法的返回值应该是
int，表示更新语句所影响的行数 - 在调用的地方必须加事务，没有事务不能正常执行
测试方法 1
不加
@Modifying注解会怎么样？
PersonRepository 类
@Query("update Person p set p.email=:email where p.id=:id")
int updateEmailById(@Param("email") String email, @Param("id") Integer id);
复制代码Test 类
@Test
public void testUpdateEmailById() {
int updateCount = repository.updateEmailById("[email protected]", 1);
System.out.println(updateCount);
}
复制代码日志信息
org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.vectorx.springdata.entities.Person p set p.email=:email where p.id=:id]; nested exception is java.lang.IllegalStateException: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.vectorx.springdata.entities.Person p set p.email=:email where p.id=:id]
//...
Caused by: java.lang.IllegalStateException: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.vectorx.springdata.entities.Person p set p.email=:email where p.id=:id]
//...
Caused by: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.vectorx.springdata.entities.Person p set p.email=:email where p.id=:id]
复制代码报错抛出了 QueryExecutionRequestException 异常，提示 Query 不支持 DML 更新操作
测试方法 2
仅仅加
@Modifying注解会怎么样？
PersonRepository 类：唯一区别就是加上 @Modifying 注解
@Modifying
@Query("update Person p set p.email=:email where p.id=:id")
int updateEmailById(@Param("email") String email, @Param("id") Integer id);
复制代码日志信息
org.springframework.dao.InvalidDataAccessApiUsageException: Executing an update/delete query; nested exception is javax.persistence.TransactionRequiredException: Executing an update/delete query
//...
Caused by: javax.persistence.TransactionRequiredException: Executing an update/delete query
//...
复制代码报错抛出了 TransactionRequiredException 异常，表明更新或删除操作必须要有一个事务
2.2、事务
Spring Data 提供了默认的事务处理方式，即所有的查询均声明为 只读事务
对于自定义的方法，如需改变 Spring Data 提供的事务默认方式，可以在方法上注解 @Transactional 声明
进行多个 Repository 操作时，也应该使它们在同一个事务中处理，按照分层架构的思想，这部分属于业务逻辑层。因此，需要在 Service 层实现对多个 Repository 的调用，并在相应的方法上声明事务
测试方法 3
@Modifying和@Transactional注解都加上
PersonService 类
@Service
public class PersonService
{
@Autowired
private PersonRepository personRepository;
@Transactional
public int updateEmailById(String email, Integer id) {
return personRepository.updateEmailById(email, id);
}
}
复制代码Test 类
public class SpringDataTest
{
private ApplicationContext context;
private PersonRepository repository;
private PersonService service;
{
context = new ClassPathXmlApplicationContext("applicationContext.xml");
repository = context.getBean(PersonRepository.class);
service = context.getBean(PersonService.class);
}
// ...
@Test
public void testUpdateEmailById() {
int updateCount = service.updateEmailById("[email protected]", 1);
System.out.println(updateCount);
}
}
复制代码日志信息
Hibernate:
update
jpa_persons
set
email=?
where
id=?
1
复制代码数据表 JPA_PERSONS 数据
结论：
1、可以通过自定义的 JPQL 完成 UPDATE 和 DELETE 操作。注意：JPQL 不支持使用 INSERT
2、在
@Query注解中编写 JPQL 语句，但必须使用@Modifying进行修饰。以通知 SpringData 这是一个 UPDATE 或 DELETE 操作3、UPDATE 或 DELETE 操作需要使用事务，此时需要定义 Service 层。在 Service 层的方法上添加事务操作
4、默认情况下，SpringData 的每个方法上有事务，但都是一个只读事务。他们不能完成修改操作！
总结
本节主要掌握 @Query 和 @Modifying 两个注解：
@Query注解支持索引参数、命名参数、模糊查询和本地查询@Modifying注解支持更新操作，如 update 和 delete，但不支持 insert（准确来说，JPQL 不支持 insert）；需要结合@Query和@Transactional注解使用
附上导图，仅供参考