jpa - Micronaut数据:创建并保存新实体

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，但是由于某种原因，我收到了 javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist异常。

Answer 1

您将ID 0传递给BookEntity构造函数以指示它是一个新实体。它与JDBC一起使用，但是当您使用JPA时，必须将0替换为null。预期的工作如下:

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))
    }
}