由于我们使用MySQL作为数据库，因此我们需要配置数据库URL，用户名和密码，以便Spring可以在启动时与数据库建立连接。打开src/main/resources/application.properties文件并向其添加以下属性 不要忘记更改spring.datasource.username和spring.datasource.password安装MySQL。此外，jpa_one_to_many_demo在继续下一部分之前，创建...
SpringDataJPA是Spring Data的一个子项目,通过提供基于JPA的Repository极大的减少了JPA作为数据访问方案的代码量,你仅仅需要编写一个接口集成下SpringDataJPA内部定义的接口即可完成简单的CRUD操作。 前言 本篇文章引导你通过Spring Boot,Spring Data JPA和MySQL实现one-to-many和many-to-one关联映射。 准备 JDK 1.8 ...
参考:https://vladmihalcea.com/a-beginners-guide-to-jpa-and-hibernate-cascade-types/ 官网文档 ,mappedBy不能用于ManyToOnne注解。 The many side of one-to-many / many-to-one bidirectional relationships must be the owning side, hence the mappedBy element cannot be specified on the ManyToOne annota...
如下代码@Entity public class Husband{ @OneToOne(cascade = CascadeType.ALL) @JoinColumn(name = "wife_id", referencedColumnName = "id") @JsonIgnoreProperties({"husband"}) private Wife wife; } @Entity public class Wife{ @OneToOne(mappedBy = "wife") @JsonIgnoreProperties({"wife"}) private...
publicclassUserimplementsSerializable{@IdprivateLong id;privateString name;privateString password;privateString phone;privateInteger age;@Column(name="role_id")privateString roleId;@OneToOne(cascade=CascadeType.DETACH,fetch=FetchType.LAZY)@JoinColumn(name="role_id",referencedColumnName="id",insertable=fal...
* 当然是通过user的card属性,让card.user与user进行关联。 * 因此,此处的mappedBy应该为被注解的属性的一个属性,被注解的属性的属性应该是本实体对应数据库表的在其他表中的一个外键。 */@OneToOne(mappedBy="card")@JsonIgnoreProperties(value="card")privateUser user;} ...
hibernate属性spring.jpa.hibernate.ddl-auto = update将根据应用程序启动时项目中的实体类自动创建/更新数据库表。 日志记录属性将帮助我们调试hibernate执行的SQL语句。 不要忘记更改spring.datasource.username并spring.datasource.password根据您的MySQL安装。另外,请jpa_one_to_one_demo在继续下一部分之前创建一个已命...
The issue I encountered was due to the absence of the child entity in hibernate.cfg.xml. The error message could use some improvement. Solution 2: Although this is an older inquiry, I would like to point out that an incompatible hibernate .hbm , mapping file , and JPA annotations can als...
JPA关联查询 因为项目中我们用到的都是双向管理关系,所以这边单向的我就不多做介绍。...1.首先是一对一关系介绍,这边一对一的关系分别是Goods和GoodsDetail(商品表和商品详细表) 关联的注释为@OneToOne Goods实体类: package com.lzq.jpa.entity...{ ...
Spring Data JDBC supports one-to-one and one-to-many (either as Set, List or Map) relationships: https://docs.spring.io/spring-data/jdbc/docs/current/reference/html/#jdbc.entity-persistence.types It would be really useful to also have th...