name = "idx_category", columnList = "category"))) class Tree { @Id @GeneratedValue(strategy = GenerationType.AUTO...gmtCreated = Date() var gmtModified = Date() var isDeleted = 0 @Version var version = 0 } GenerationType...* * @see GeneratedValue * * @since Java Persistence 1.0 */ public enum GenerationType { /*
主键配置 @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "cust_id")...private Long custId;//主键 @Id：表示这个注解表示此属性对应数据表中的主键 @GeneratedValue(strategy = GenerationType.IDENTITY...strategy表示此注解使用的策略，可以使用GenerationType.IDENTITY、GenerationType.SEQUENCE、GenerationType.TABLE、GenerationType.AUTO...GenerationType.IDENTITY：底层数据库必须支持自动增长，（类似于mysql的自增） GenerationType.SEQUENCE：底层数据库必须支持序列，（Oracle...） GenerationType.TABLE：jpa提供的一种机制，通过一张数据表的形式帮助完成主键自增 GenerationType.AUTO：程序自动选择合适的主键生成策略
lombok.Builder; import lombok.Data; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...1.1.1、GenerationType.TABLE:使用表生产主键，即使用另外一张表单独维护主键。...: 主键自增 mysql 中的 auto_increment */ @Id @GeneratedValue(strategy =GenerationType.IDENTITY...) private Long uid; 1.1.4、GenerationType.AUTO：自动创建主键（以上三种策略任选一种） @Table(name = "user_info") public...class UserInfo implements Serializable { /** * 表主键 @Id :表示该字段是表主键 * strategy = GenerationType.AUTO
Users 实体 @Entity @Table(name="t_users") public class Users implements Serializable{ @Id //strategy=GenerationType.IDENTITY...自增长 @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="userid") private Integer userid...} } 创建 Roles 实体 @Entity @Table(name="t_roles") public class Roles { @Id @GeneratedValue(strategy=GenerationType.IDENTITY...多方 pojo @Entity @Table(name="t_users") public class Users implements Serializable{ @Id //strategy=GenerationType.IDENTITY...自增长 @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="userid") private Integer userid
示例代码@Entitypublic class Person { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private...示例代码@Entitypublic class Department { @Id @GeneratedValue(strategy = GenerationType.IDENTITY)...ArrayList(); // 省略getter和setter}@Entitypublic class Employee { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...示例代码@Entitypublic class Student { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private...HashSet(); // 省略getter和setter}@Entitypublic class Course { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
strategy() default AUTO; String generator() default ""; } 其中GenerationType: public...enum GenerationType{ TABLE, SEQUENCE, IDENTITY, AUTO } JPA提供的四种标准用法为...分别介绍其他三个: 1.SEQUENCE 实体类中的注解 @Id @GeneratedValue(strategy =GenerationType.SEQUENCE,generator="aaa"...2.IDENTITY 主键则由数据库自动维护，使用起来很简单 @Id @GeneratedValue(strategy = GenerationType.IDENTITY) 3、AUTO 默认的配置...@Id @GeneratedValue(strategy = GenerationType.AUTO) 二、hibernate主键策略生成器 hibernate提供多种主键生成策略，有点是类似于
import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...Table(name = "teacher") @Getter @Setter public class Teacher { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...name = "student") @Getter @Setter public class Student { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType
@Target({METHOD, FIELD})@Retention(RUNTIME)public @interface GeneratedValue { GenerationType strategy...这是一个可选项，默认是 GenerationType.AUTO；strategy 的值是主键生成策略枚举类型 GenerationType，包含4个枚举值：【TABLE，SEQUENCE，IDENTITY...包含如下：3.1 GenerationType.TABLETABLE 指示持久化提供程序必须使用基础数据库表为实体分配主键，以确保唯一性。...3.2 GenerationType.SEQUENCESEQUENCE 指示持久化提供程序必须使用数据库序列为实体分配主键。该策略只适用于部分支持 序列 的数据库系统，比如 Oracle。...3.3 GenerationType.IDENTITYIDENTITY 指示持久化提供程序必须使用数据库标识列为实体分配主键。该策略只适用于支持 主键自增长 的数据库系统，比如 MySQL。
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType
Data @Entity @Table(name = "t_address") public class Address { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...Data @Entity @Table(name = "t_school") public class School { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...Data @Entity @Table(name = "t_address") public class Address { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...Data @Entity @Table(name = "t_school") public class School { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...@Data @Table(name = "t_clazz") @Entity public class Clazz { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...Table(name = "users") public class Users implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType
以下是一个简单的示例： @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...fields, getters, and setters } @Entity public class Role { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...以下是具体实现： // User.java @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...getters, and setters } // Role.java @Entity public class Role { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...com.fasterxml.jackson.annotation.JsonBackReference; @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
基本数据类型数组的存储 假设我们有一个包含基本数据类型数组的实体类： @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...例如： @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private...// Getters and Setters } @Entity public class Address { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...JPA并结合JSON序列化工具（如Jackson）来实现这一方法： @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...XML 我们可以使用JPA并结合JAXB进行XML序列化和反序列化： @Entity public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
@Entitypublic class One { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long...@Entitypublic class Many { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long...首先，我们创建Author实体类：@Entitypublic class Author { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...构造函数、getter和setter方法}然后，我们创建Book实体类：@Entitypublic class Book { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
userinfo @Entity @Table(name = "userinfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...usercode @Entity @Table(name = "code") public class UserCode { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...实体类 @Entity @Table(name = "userinfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...hobby实体类 @Entity @Table(name = "hobby") public class Hobby { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...实体类 @Entity @Table(name = "userinfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
@GeneratedValue(strategy = GenerationType.IDENTITY)：该注解指定了主键的生成策略，一般不单独出现，这里指定了主键自增的策略。 ?...例如： @Entity @Table(name = "userInfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...使用使用@GeneratedValue指定主键的生成策略，通过它的strategy属性来指定具体的主键生成方案，该属性可以取如下几个值： GenerationType.AUTO：hibernate默认为该值...，它指明了hibernate自动根据底层数据库选择适当的生成策略 GenerationType.IDENTITY：适用于MySQL，SQLserver的主键自增长策略 GenerationType.SEQUENCE...：适用于Oracle的子串策略 GenerationType.TABLE：基于辅助表的生成主键策略 如果不是使用Oracle做数据库的话，一般我们会使用IDENTITY作为默认的主键生成策略。
代码示例懒加载示例@Entitypublic class Department { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...employees; // 省略getter和setter}@Entitypublic class Employee { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...// 省略其他属性和getter/setter}即时加载示例@Entitypublic class Book { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...author; // 省略getter和setter}@Entitypublic class Author { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...String title; private Set answer; @Id @GeneratedValue(strategy = GenerationType.IDENTITY...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...User userid;//教师id private Questions question; @Id @GeneratedValue(strategy = GenerationType.IDENTITY
具体说明如下： IDENTITY:主键由数据库自动生成（主要是自动增长型） 用法： @Id @GeneratedValue(strategy = GenerationType.IDENTITY...用法： @Id @GeneratedValue(strategy = GenerationType.SEQUENCE,generator="payablemoney_seq")...int allocationSize() default 50; } AUTO：主键由程序控制 @Id @GeneratedValue(strategy = GenerationType.AUTO...) private Long custId; TABLE：使用一个特定的数据库表格来保存主键 用法： @Id @GeneratedValue(strategy = GenerationType.TABLE
unique = true, columnList = "url"))) open class TechArticle { @Id @GeneratedValue(strategy = GenerationType.IDENTITY....* import javax.persistence.Entity import javax.persistence.GeneratedValue import javax.persistence.GenerationType...import javax.persistence.Id @Entity class TechArticleTag { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
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