Micronaut 数据：创建和保存新实体

Question

我想在应用程序启动期间保留新实体，如下所示：

class Application(
    private val bookRepository: BookRepository,
) {
    @EventListener
    fun init(event: StartupEvent) {
        val encyclopedia = BookEntity(0, "The sublime source of knowledge")
        val notebook = BookEntity(0, "Release your creativity!")
        bookRepository.saveAll(listOf(encyclopedia, notebook))
    }
}

根据the documentation 这应该可以工作，但由于某种原因我得到javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist 异常。

Answer 1

您将 ID 0 传递给 BookEntity 构造函数以表明它是一个新实体。它适用于 JDBC，但是当您使用 JPA 时，0 必须替换为 null。以下按预期工作：

class Application(
    private val bookRepository: BookRepository,
) {
    @EventListener
    fun init(event: StartupEvent) {
        val encyclopedia = BookEntity(null, "The sublime source of knowledge")
        val notebook = BookEntity(null, "Release your creativity!")
        bookRepository.saveAll(listOf(encyclopedia, notebook))
    }
}