我试图弄清楚如何在会话缓存中保持数据同步。我有以下示例:
@Table (name = "language")
@Entity
public class Language
{
@Id
@Column (name = "key", unique = true, nullable = false)
private String key;
@Column (name = "name", unique = true, nullable = false)
private String name;
@OneToMany (mappedBy = "language", cascade = { CascadeType.DETACH, CascadeType.REFRESH, CascadeType.REMOVE })
private Set<Translation> translations;
}
@Table (name = "translation")
@Entity
public class Translation
{
@Id
@GeneratedValue (strategy = GenerationType.SEQUENCE)
private Long id;
@ManyToOne(optional = false)
private Language language;
@ManyToOne (optional = false)
@JoinColumn(referencedColumnName = "key")
private TranslatableEntity translatable;
@Column(name = "value")
private String value;
}
@Table (name = "translatable")
@Entity
public class Translatable
{
@Id
@GeneratedValue (strategy = GenerationType.SEQUENCE)
private Long id;
@NotNull
@Size (max = 255)
@Column (name = "key", unique = true, nullable = false)
private String key;
@OneToMany (mappedBy = "translatable", cascade = { CascadeType.DETACH, CascadeType.REFRESH, CascadeType.REMOVE, CascadeType.PERSIST })
@MapKey (name = "language")
private Map<Language, Translation> translations;
}
基本上我这样做:
// Print current translations for en language
Language language = languageRepository.getOne("en");
printTranslations(language);
// Add new translatable object with translation for english language
Translatable translatable = new Translatable();
translatable.addTranslation("en", "...")
translatableRepository.saveAndFlush(translatable)
// Again print translations for en language
// This still prints outdated information
language = languageRepository.getOne("en");
printTranslations(language);
所以我的问题是如何保持数据的一致性。
当插入/删除具有一些翻译的新翻译时,语言实例中的翻译列表不会在会话高速缓存中更新。我找不到任何令人满意的答案。这一个最接近:Keeping entity relationship in sync when deleting child in JPA。
谢谢
JPA不会为您维护双向关系的双方。第一级缓存的目的是在事务实体内只加载一次。
这为您提供了两个解决问题的方法:
Translatable.add
方法,以便更新Language.translations
和Translation.language
language
之前,通过驱逐或关闭会话(即交易)强制重新加载languageRepository.getOne("en")