摘要: 原创出处 http://www.iocoder.cn/Spring-Boot/JPA/ 「芋道源码」欢迎转载,保留摘要,谢谢!
示例代码对应仓库:lab-13-jpa 。
在 Spring Data 中,支持根据方法名作生成对应的查询(WHERE
)条件,进一步进化我们使用 JPA ,具体是方法名以 findBy
、existsBy
、countBy
、deleteBy
开头,后面跟具体的条件。具体的规则,在 《Spring Data JPA —— Query Creation》 文档中,已经详细提供。如下:
关键字 | 方法示例 | JPQL snippet |
---|---|---|
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 ages) | … where x.age in ?1 |
NotIn | findByAgeNotIn(Collection 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) |
OrderBy
关键字。下面,我们来编写一个简单的示例。
艿艿:IDEA 牛逼,提供的插件已经能够自动提示上述关键字。太强了~
在 cn.iocoder.springboot.lab13.mybatis.repository
包路径下,创建 UserRepository03 接口。代码如下:
// UserRepository03.java
public interface UserRepository03 extends PagingAndSortingRepository<UserDO, Integer> {
UserDO findByUsername(String username);
Page<UserDO> findByCreateTimeAfter(Date createTime, Pageable pageable);
}
创建 UserRepository03Test 测试类,我们来测试一下简单的 UserRepository03 的每个操作。代码如下:
// UserRepository03.java
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserRepository03Test {
@Autowired
private UserRepository03 userRepository;
@Test
public void testFindByUsername() {
UserDO user = userRepository.findByUsername("yunai");
System.out.println(user);
}
@Test
public void testFindByCreateTimeAfter() {
// 创建分页条件
Pageable pageable = PageRequest.of(1, 10);
// 执行分页操作
Date createTime = new Date(2018 - 1990, Calendar.FEBRUARY, 24); // 临时 Demo ,实际不建议这么写
Page<UserDO> page = userRepository.findByCreateTimeAfter(createTime, pageable);
// 打印
System.out.println(page.getTotalElements());
System.out.println(page.getTotalPages());
}
}
具体的,胖友可以自己跑跑,妥妥的。