java - 使用一对一关系时如何解决“具有相同标识符值的不同对象已与 session 关联”错误

我正在尝试在2个实体之间创建一对一关系：


项目实体

@Entity
@Table(name = "projects")
public class Project {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @OneToOne(mappedBy = "project", cascade = CascadeType.ALL, optional = false, fetch = FetchType.LAZY)
    private CrawlerConfiguration crawlerConfiguration;

    // Getters and setters ...

    public void setCrawlerConfiguration(CrawlerConfiguration crawlerConfiguration) {
        if (crawlerConfiguration == null) {
            if (this.crawlerConfiguration != null) {
                this.crawlerConfiguration.setProject(null);
            }
        } else {
            crawlerConfiguration.setProject(this);
        }

        this.crawlerConfiguration = crawlerConfiguration;
    }

CrawlerConfiguration实体

@Entity
@Table(name = "crawler_configurations")
public class CrawlerConfiguration {

    @Id
    private Long id;

    @OneToOne(fetch = FetchType.LAZY)
    @MapsId
    private Project project;

    // Getters and setters ...
}

用户创建新项目时，还应为该项目创建配置。

@Transactional
public Project createProject(Project project) {
    project.setCrawlerConfiguration(new CrawlerConfiguration());
    return projectRepository.save(project);
}

不幸的是，它导致以下异常：


javax.persistence.EntityExistsException：与对象不同的对象
相同的标识符值已与会话相关联：
[com.github.peterbencze.serritorcloud.model.entity.CrawlerConfiguration＃1]


创建实体的正确方法是什么？

最佳答案

试试这个

 @OneToOne(fetch = FetchType.LAZY)
 @PrimaryKeyJoinColumn
 private Project project;

在您的CrawlerConfiguration实体中