spingboot集成jpa(二）

 一、使用单元测试

单元测试在每个项目环境中必不可少，springboot中如何使用单元测试

在src/test/java中新建测试类DemoApplicationTest.java

项目结构：

DemoApplicaytionTest.java内容

package springboot_jpa_jsp;


import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.king.app.App;
import com.king.entity.User;
import com.king.service.UserService;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = App.class)
public class DemoApplicaytionTest {
    
    @Autowired
    private UserService userService;
    
    @Test
    public void testUser() {
        User u = userService.findOne("1");
        System.out.println(u.toString());
    }
}

此时，直接右键运行Junit测试即可

二、查询方法

1. 使用jpa的命名查询

当使用findBy/readBy/getBy + 某个字段时，比如：

User findById(String id);

也可以多字段查询，如：

List<User> findByCodeAndUsername(String code,String username);

spring jpa的相关命名规则如下：

Keyword	Sample	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	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<Age> ages)	… where x.age in ?1
NotIn	findByAgeNotIn(Collection<Age> age)	… 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)

2. 自定义注解查询

除了继承JpaRepository中的命名方法，有时候不可避免的要自定义查询方法。上面的单元测试中findOne就是自定义的查询方法。

 使用@Query注解来查询，注解查询本质上仍然使用的是HQL语法，所以下面的是针对对象查询的。(我在测试时由于粗心大意将User写成user被坑了不少时间)

    @Query("select u from User u where u.id = :id")
    User findOne(@Param("id")String id);