java - Hibernate 序列 ID 规范

Question

我有这个注释来指定序列 ID:

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "parametro_seq_gen")
@SequenceGenerator(name = "parametro_seq_gen", sequenceName = "PARAMETROS_SQ",
      allocationSize = 1, initialValue = 1)

我发现在我的所有实体上重复非常冗长。

有什么方法可以创建自定义注释或其他东西吗？我只想指定序列名称。

Answer 1

这很简单!

只需创建一个存储实体的package-info.java，并在其中提供全局@GenericGenerator:

@GenericGenerator(
    name = "pooled",
    strategy = "org.hibernate.id.enhanced.SequenceStyleGenerator",
    parameters = {
        @Parameter(name = "sequence_name", value = "sequence"),
        @Parameter(name = "initial_value", value = "1"),
        @Parameter(name = "increment_size", value = "5"),
    }
)
package com.vladmihalcea.book.hpjp.hibernate.identifier.globalsequence;

然后您的实体可以共享池通用生成器，如下所示:

@Entity(name = "Post")
public class Post {

    @Id
    @GeneratedValue(generator = "pooled")
    private Long id;
}

@Entity(name = "Announcement")
public class Announcement {

    @Id
    @GeneratedValue(generator = "pooled")
    private Long id;
}

您需要使用@GenericGenerator，因为@SequenceGenerator不适用于包。

就是这样!