java JpaRepository findAll() 返回空结果
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JpaRepository findAll() returns empty result
提问by fiskra
JpaRepositoryfindAll()method returns empty result. I am trying to implement rest service by using Spring-boot, h2 database and jpa.
JpaRepositoryfindAll()方法返回空结果。我正在尝试使用 Spring-boot、h2 数据库和 jpa 来实现休息服务。
Here is my schema.sql
这是我的 schema.sql
CREATE TABLE IF NOT EXISTS `City` (
`city_id` bigint(20) NOT NULL auto_increment,
`city_name` varchar(200) NOT NULL,
PRIMARY KEY (`city_id`));
My data.sqlfile includes :
我的data.sql文件包括：
INSERT INTO City (city_id,city_name) VALUES(1,'EDE');
INSERT INTO City (city_id,city_name) VALUES(2,'DRUTEN');
INSERT INTO City (city_id,city_name) VALUES(3,'DELFT');
The Cityentity :
该City实体：
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "City")
public class City {
@Id
@GeneratedValue
@Column(name = "city_id")
private Long cityId;
@Column(name = "city_name")
private String cityName;
public Long getCityId() {
return cityId;
}
public void setCityId(Long cityId) {
this.cityId = cityId;
}
public String getCityName() {
return cityName;
}
public void setCityName(String cityName) {
this.cityName = cityName;
}
}
The JpaRepositoryinterface:
该JpaRepository接口：
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
@Repository
public interface CityRepository extends JpaRepository<City, Long> {
@Override
List<City> findAll();
}
And here is my Contollerclass
这是我的Contoller班级
@RestController
@RequestMapping("/city")
public class CityController {
@Autowired
private CityRepository cityRepository;
@RequestMapping(method = RequestMethod.GET, value = "/all")
public List<City> getAllCityList(){
return cityRepository.findAll();
}
}
What am I doing wrong here? The reference documentation : Spring doc
我在这里做错了什么？参考文档：Spring doc
回答by M. Deinum
You have a schema.sqland data.sqlwhich are both executed after the DataSourcehas been configured and is ready. Next the EntityManagerFactoryis created and by default (See the reference guide) this will create-dropthe database for embedded types (like H2).
您有一个schema.sql和data.sql，它们都在DataSource配置完成并准备就绪后执行。接下来EntityManagerFactory创建，默认情况下（参见参考指南）这将create-drop是嵌入类型（如 H2）的数据库。
You can override this behavior by changing the spring.jpa.hibernate.ddl-autoproperty to anything else then createor create-drop.
您可以通过将spring.jpa.hibernate.ddl-auto属性更改为其他任何内容 thencreate或来覆盖此行为create-drop。
Another solution is to rename your data.sqlto import.sqlwhich will be executed after Hibernate created the schema for you. You can now obviously also remove the schema.sqlas Hibernate will create the schema.
另一种解决方案是将您的重命名data.sql为import.sql将在 Hibernate 为您创建架构后执行的。您现在显然也可以删除schema.sqlHibernate 将创建模式。
If this is for learning purposes you should be fine, if you want to use this in a live production system I suggest instead of using this to use something like Flywayto manage your schema.
如果这是出于学习目的，您应该没问题，如果您想在实时生产系统中使用它，我建议您不要使用它来使用Flyway 之类的东西来管理您的架构。
回答by Reborn
As far as i understood, you want to execute sql scripts on application startup and after that use Hibernate? Well, you have to use one of the options mentioned here, and set spring.jpa.hibernate.ddl-auto=none.The explanation is given there.
据我了解，您想在应用程序启动时执行 sql 脚本，然后再使用 Hibernate？好吧，你必须使用这里提到的选项之一，并设置spring.jpa.hibernate.ddl-auto=none。解释在那里给出。
Good luck
祝你好运
回答by Samuel Gwokuda
In my case I had the deleted column as null and had @Where(clause = "deleted='false'") on the JPA Entity
在我的情况下，我将删除的列设置为空，并在 JPA 实体上设置了 @Where(clause = "deleted='false'")
