JPA编写拼接方法名实现条件查询

虽然接口预置的方法使用起来非常方便，但是如果我们需要进行条件查询等操作或是一些判断，就需要自定义一些方法来实现，同样的，我们不需要编写SQL语句，而是通过方法名称的拼接来实现条件判断，这里列出了所有支持的条件判断名称：

属性	拼接方法名称示例	执行的语句
Distinct	findDistinctByLastnameAndFirstname	select distinct … where x.lastname = ?1 and x.firstname = ?2
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（参数与附加%绑定）
EndingWith	findByFirstnameEndingWith	… where x.firstname like ?1（参数与前缀%绑定）
Containing	findByFirstnameContaining	… where x.firstname like ?1（参数绑定以%包装）
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.firstname) = UPPER(?1)

比如我们想要实现根据用户名模糊匹配查找用户：

@Repository
public interface AccountRepository extends JpaRepository<Account, Integer> {
    //按照表中的规则进行名称拼接，不用刻意去记，IDEA会有提示
    List<Account> findAllByUsernameLike(String str);
}

我们来测试一下：

@Test
void contextLoads() {
    repository.findAllByUsernameLike("%明%").forEach(System.out::println);
}