- android - 多次调用 OnPrimaryClipChangedListener
- android - 无法更新 RecyclerView 中的 TextView 字段
- android.database.CursorIndexOutOfBoundsException : Index 0 requested, 光标大小为 0
- android - 使用 AppCompat 时,我们是否需要明确指定其 UI 组件(Spinner、EditText)颜色
我是 Spring Data 的新手,并尝试通过关注 this post on SO 来解决此问题和其他一些教程,但没有太大的成功。
我正在尝试在 2 个表之间使用 Spring Data JPA 进行简单的联接。
数据库中的表被称为:
* user_vehicle -> 包含每个用户所有车辆的信息,因为 1 个用户可以拥有许多车辆
* vehicle_model 包含有关车辆模型的数据(id、名称等)
user_vehicle 表中数据库中的当前数据:
身份证 |车辆编号 |用户身份
1 | 1 | 1
2 | 2 | 1
这是我尝试过但无法正常工作的代码(从帖子中删除了 getter 和 setter 以缩短它):
@Entity(name = "vehicle_model")
public class VehicleModel {
@Id
@Min(1)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long manufacturerId;
private String title;
private int ccm;
private int kw;
private int yearOfManufacture;
private int engineTypeId;
private boolean isActive;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "vehicle_id", insertable = false, updatable = false)
@Fetch(FetchMode.JOIN)
private UserVehicle userVehicle;
}
@Entity(name = "user_vehicle")
public class UserVehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
@Column(nullable = false)
private long vehicleId;
@Column(nullable = false)
private long userId;
@OneToMany(targetEntity = VehicleModel.class, mappedBy = "userVehicle", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
List<VehicleModel> vehicleModels;
}
@Repository
public interface UserVehicleRepository extends CrudRepository<UserVehicle, Long>
{
Iterable<UserVehicle> findVehicleModelsByUserId(Long userId);
}
2019-06-23 02:04:10.988 DEBUG 5896 --- [nio-8080-exec-1] org.hibernate.SQL : select uservehicl0_.id as id1_1_, uservehicl0_.user_id as user_id2_1_, uservehicl0_.vehicle_id as vehicle_3_1_ from user_vehicle uservehicl0_ where uservehicl0_.user_id=?
2019-06-23 02:04:11.034 DEBUG 5896 --- [nio-8080-exec-1] org.hibernate.SQL : select vehiclemod0_.vehicle_id as vehicle_9_4_0_, vehiclemod0_.id as id1_4_0_, vehiclemod0_.id as id1_4_1_, vehiclemod0_.ccm as ccm2_4_1_, vehiclemod0_.engine_type_id as engine_t3_4_1_, vehiclemod0_.is_active as is_activ4_4_1_, vehiclemod0_.kw as kw5_4_1_, vehiclemod0_.manufacturer_id as manufact6_4_1_, vehiclemod0_.title as title7_4_1_, vehiclemod0_.vehicle_id as vehicle_9_4_1_, vehiclemod0_.year_of_manufacture as year_of_8_4_1_ from vehicle_model vehiclemod0_ where vehiclemod0_.vehicle_id=?
2019-06-23 02:04:11.035 WARN 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1054, SQLState: 42S22
2019-06-23 02:04:11.035 ERROR 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : Unknown column 'vehiclemod0_.vehicle_id' in 'field list'
2019-06-23 02:04:11.036 DEBUG 5896 --- [nio-8080-exec-1] org.hibernate.SQL : select vehiclemod0_.vehicle_id as vehicle_9_4_0_, vehiclemod0_.id as id1_4_0_, vehiclemod0_.id as id1_4_1_, vehiclemod0_.ccm as ccm2_4_1_, vehiclemod0_.engine_type_id as engine_t3_4_1_, vehiclemod0_.is_active as is_activ4_4_1_, vehiclemod0_.kw as kw5_4_1_, vehiclemod0_.manufacturer_id as manufact6_4_1_, vehiclemod0_.title as title7_4_1_, vehiclemod0_.vehicle_id as vehicle_9_4_1_, vehiclemod0_.year_of_manufacture as year_of_8_4_1_ from vehicle_model vehiclemod0_ where vehiclemod0_.vehicle_id=?
2019-06-23 02:04:11.037 WARN 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1054, SQLState: 42S22
2019-06-23 02:04:11.037 ERROR 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : Unknown column 'vehiclemod0_.vehicle_id' in 'field list'
2019-06-23 02:04:11.038 DEBUG 5896 --- [nio-8080-exec-1] org.hibernate.SQL : select vehiclemod0_.vehicle_id as vehicle_9_4_0_, vehiclemod0_.id as id1_4_0_, vehiclemod0_.id as id1_4_1_, vehiclemod0_.ccm as ccm2_4_1_, vehiclemod0_.engine_type_id as engine_t3_4_1_, vehiclemod0_.is_active as is_activ4_4_1_, vehiclemod0_.kw as kw5_4_1_, vehiclemod0_.manufacturer_id as manufact6_4_1_, vehiclemod0_.title as title7_4_1_, vehiclemod0_.vehicle_id as vehicle_9_4_1_, vehiclemod0_.year_of_manufacture as year_of_8_4_1_ from vehicle_model vehiclemod0_ where vehiclemod0_.vehicle_id=?
2019-06-23 02:04:11.039 WARN 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1054, SQLState: 42S22
2019-06-23 02:04:11.040 ERROR 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : Unknown column 'vehiclemod0_.vehicle_id' in 'field list'
2019-06-23 02:04:11.042 DEBUG 5896 --- [nio-8080-exec-1] org.hibernate.SQL : select vehiclemod0_.vehicle_id as vehicle_9_4_0_, vehiclemod0_.id as id1_4_0_, vehiclemod0_.id as id1_4_1_, vehiclemod0_.ccm as ccm2_4_1_, vehiclemod0_.engine_type_id as engine_t3_4_1_, vehiclemod0_.is_active as is_activ4_4_1_, vehiclemod0_.kw as kw5_4_1_, vehiclemod0_.manufacturer_id as manufact6_4_1_, vehiclemod0_.title as title7_4_1_, vehiclemod0_.vehicle_id as vehicle_9_4_1_, vehiclemod0_.year_of_manufacture as year_of_8_4_1_ from vehicle_model vehiclemod0_ where vehiclemod0_.vehicle_id=?
2019-06-23 02:04:11.043 WARN 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1054, SQLState: 42S22
2019-06-23 02:04:11.043 ERROR 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : Unknown column 'vehiclemod0_.vehicle_id' in 'field list'
2019-06-23 02:04:11.045 DEBUG 5896 --- [nio-8080-exec-1] org.hibernate.SQL : select vehiclemod0_.vehicle_id as vehicle_9_4_0_, vehiclemod0_.id as id1_4_0_, vehiclemod0_.id as id1_4_1_, vehiclemod0_.ccm as ccm2_4_1_, vehiclemod0_.engine_type_id as engine_t3_4_1_, vehiclemod0_.is_active as is_activ4_4_1_, vehiclemod0_.kw as kw5_4_1_, vehiclemod0_.manufacturer_id as manufact6_4_1_, vehiclemod0_.title as title7_4_1_, vehiclemod0_.vehicle_id as vehicle_9_4_1_, vehiclemod0_.year_of_manufacture as year_of_8_4_1_ from vehicle_model vehiclemod0_ where vehiclemod0_.vehicle_id=?
2019-06-23 02:04:11.046 WARN 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1054, SQLState: 42S22
2019-06-23 02:04:11.046 ERROR 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : Unknown column 'vehiclemod0_.vehicle_id' in 'field list'
2019-06-23 02:04:11.048 DEBUG 5896 --- [nio-8080-exec-1] org.hibernate.SQL : select vehiclemod0_.vehicle_id as vehicle_9_4_0_, vehiclemod0_.id as id1_4_0_, vehiclemod0_.id as id1_4_1_, vehiclemod0_.ccm as ccm2_4_1_, vehiclemod0_.engine_type_id as engine_t3_4_1_, vehiclemod0_.is_active as is_activ4_4_1_, vehiclemod0_.kw as kw5_4_1_, vehiclemod0_.manufacturer_id as manufact6_4_1_, vehiclemod0_.title as title7_4_1_, vehiclemod0_.vehicle_id as vehicle_9_4_1_, vehiclemod0_.year_of_manufacture as year_of_8_4_1_ from vehicle_model vehiclemod0_ where vehiclemod0_.vehicle_id=?
2019-06-23 02:04:11.049 WARN 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1054, SQLState: 42S22
2019-06-23 02:04:11.049 ERROR 5896 --- [nio-8080-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : Unknown column 'vehiclemod0_.vehicle_id' in 'field list'
最佳答案
在这里找到了解决方案:https://www.baeldung.com/jpa-many-to-many
因为这是一个多对多关系,所以我一直在看它有点不对劲。我的想法是转到“中间”表并选择 userId = :id 的所有 vehicle_id 并从 vehicle_ids 列表中获取每辆车的详细信息。
这是有效的正确实现:
@Entity(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String username;
private String password;
private String firstName;
private String lastName;
private boolean isActive;
@OneToMany(mappedBy = "user")
private Set<UserVehicle> userVehicles;
@Entity(name = "user_vehicle")
public class UserVehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private boolean isActive;
@ManyToOne
@JoinColumn(name = "vehicle_id")
private Vehicle vehicle;
@ManyToOne
@JoinColumn(name = "user_id")
private User user;
@Entity(name = "vehicle_model")
public class Vehicle {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private Long manufacturerId;
private String title;
private int ccm;
private int kw;
private int yearOfManufacture;
private int engineTypeId;
private boolean isActive;
@OneToMany(mappedBy = "vehicle")
private Set<UserVehicle> userVehicles;
public interface UserVehicleRepository extends CrudRepository<UserVehicle, Long> {
Iterable<UserVehicle> findVehicleModelsByUserId(Long userId);
[
{
"id": 2,
"vehicle": {
"id": 2,
"manufacturerId": 1,
"title": "Fazer FZ1S",
"ccm": 998,
"kw": 110,
"yearOfManufacture": 2008,
"engineTypeId": 1,
"active": true
},
"user": {
"id": 2,
"username": "sfajkovic",
"password": "33",
"firstName": "Ivan",
"lastName": "Fajkovic",
"active": true
},
"active": true
}
]
关于java - 无法使用 Spring Data JPA 创建 JOIN,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56720048/
我尝试阅读有关 Spring BOM、Spring Boot 和 Spring IO 的文档。 但是没有说明,我们应该如何一起使用它们? 在我的项目中,我们已经有了自己的 Parent POM ,所以
我正在开发的很酷的企业应用程序正在转向 Spring。这对所有团队来说都是非常酷和令人兴奋的练习,但也是一个巨大的压力源。我们所做的是逐渐将遗留组件移至 Spring 上下文。现在我们有一个 huuu
我正在尝试使用 @Scheduled 运行 Spring 批处理作业注释如下: @Scheduled(cron = "* * * * * ?") public void launchMessageDi
我对这两个概念有点困惑。阅读 Spring 文档,我发现,例如。 bean 工厂是 Spring 容器。我还读到“ApplicationContext 是 BeanFactory 的完整超集”。但两者
我们有一个使用 Spring BlazeDS 集成的应用程序。到目前为止,我们一直在使用 Spring 和 Flex,它运行良好。我们现在还需要添加一些 Spring MVC Controller 。
假设我有一个类(class) Person带属性name和 age ,它可以像这样用 Spring 配置: 我想要一个自定义的 Spring 模式元素,这很容易做到,允许我在我的 Sp
如何在 Java 中以编程方式使用 Spring Data 创建 MongoDB 复合索引? 使用 MongoTemplate 我可以创建一个这样的索引:mongoTemplate.indexOps(
我想使用 spring-complex-task 执行我的应用程序,并且我已经构建了复杂的 spring-batch Flow Jobs,它执行得非常好。 你能解释一下spring批处理流作业与spr
我实现了 spring-boot 应用程序,现在我想将它用作非 spring 应用程序的库。 如何初始化 lib 类,以便 Autowiring 的依赖项按预期工作?显然,如果我使用“new”创建类实
我刚开始学习 spring cloud security,我有一个基本问题。它与 Spring Security 有何不同?我们是否需要在 spring boot 上构建我们的应用程序才能使用 spr
有很多人建议我使用 Spring Boot 而不是 Spring 来开发 REST Web 服务。我想知道这两者到底有什么区别? 最佳答案 总之 Spring Boot 减少了编写大量配置和样板代码的
您能向我解释一下如何使用 Spring 正确构建 Web 应用程序吗?我知道 Spring 框架的最新版本是 4.0.0.RELEASE,但是 Spring Security 的最新版本是 3.2.0
我如何才能知道作为 Spring Boot 应用程序的一部分加载的所有 bean 的名称?我想在 main 方法中有一些代码来打印服务器启动后加载的 bean 的详细信息。 最佳答案 如spring-
我有一个使用 Spring 3.1 构建的 RESTful API,也使用 Spring Security。我有一个 Web 应用程序,也是一个 Spring 3.1 MVC 应用程序。我计划让移动客
升级到 Spring 5 后,我在 Spring Rabbit 和 Spring AMQP 中遇到错误。 两者现在都设置为 1.5.6.RELEASE 有谁知道哪些版本应该与 Spring 5 兼容?
我现在已经使用 Spring Framework 3.0.5 和 Spring Security 3.0.5 多次了。我知道Spring框架使用DI和AOP。我还知道 Spring Security
我收到错误 Unable to Location NamespaceHandler when using context:annotation-config running (java -jar) 由
在 Spring 应用程序中嵌入唯一版本号的策略是什么? 我有一个使用 Spring Boot 和 Spring Web 的应用程序。 它已经足够成熟,我想对其进行版本控制并在运行时看到它显示在屏幕上
我正在使用 spring data jpa 进行持久化。如果存在多个具有相同名称的实体,是否有一种方法可以将一个实体标记为默认值。类似@Primary注解的东西用来解决多个bean的依赖问题 @Ent
我阅读了 Spring 框架的 DAOSupport 类。但是我无法理解这些 DAOSuport 类的优点。在 DAOSupport 类中,我们调用 getXXXTemplate() 方法来获取特定的
我是一名优秀的程序员,十分优秀!