JPA Hibernate 中 String 类型的主键 Id

generation strategy

• Numerical identifier，数值型，非String类型主键，即 long、short、int
  • 不指定具体策略
    • Hibernate 将默认使用GenerationType.AUTO，根据底层数据库选择下面某一种
      • identity
      • sequence
      • table
  • 指定具体策略
    • strategy = GenerationType.IDENTITY
    • strategy = GenerationType.SEQUENCE
    • strategy = GenerationType.TABL
• UUID identifier，String 类型

DEMO

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通常是 Number 类型做主键
@Id
@GeneratedValue //不指定具体策略
@Column(name = "id", nullable = false)
private Long id;
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@Id
@GeneratedValue(strategy = GenerationType.IDENTITY) //指定具体策略
@Column(name = "id", nullable = false)
private Long id;
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特例 用 String 类型做主键
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid2")
@Column(name = "PR_KEY")
private String prKey;
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参考

• https://stackoverflow.com/questions/18622716/how-to-use-id-with-string-type-in-jpa-hibernate?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa