一个profile对象有一个任务列表。当保存一个新的profile时,任务列表也应该与数据库同步(插入或更新)。问题是profile-repository的save()方法只允许一种方法,具体取决于属性上方设置的cascade属性(CascadeType.PERSIST或MERGE).
Profile类
@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
public abstract class AbstractProfile implements Profile {
...
@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.PERSIST)
private List<Task> tasks;
..
JUnit测试类
public class ProfileTaskRepositoryTest {
@Autowired
private ProfileRepository profileRepo; //extends JpaRepository
@Autowired
private TaskRepository taskRepo; //extends JpaRepository
@Test // ->this test passes
public void testCreateProfileWithNewTask() {
//profileData and taskData hold dummy data. They return new objects
AbstractProfile interview = profileData.createITInterviewProfile();
Task questionTask = taskData.createInterviewQuestionTask();
//add new task to profile and save
interview.addTask(questionTask);
profileRepo.save(interview);
//task repository confirms the insertion
assertTrue(taskRepo.count() == 1);
}
@Test // ->this test fails
public void testCreateProfileWithExistingTask() {
//first create task and save in DB
Task questionTask = taskData.createInterviewQuestionTask(); // transient obj
taskRepo.save(questionTask); // questionTask becomes detached
// then create a new profile and add the existing task.
// the problem is the existing task is now detached)
AbstractProfile interview = profileData.createITInterviewProfile();
interview.addTask(questionTask);
profileRepo.save(interview); // !!! this throws an exception
}
我想,当taskRepo将questionTask对象保存在数据库中并关闭会话时,它就变成了分离状态。
异常:
org.springframework.orm.jpa.JpaSystemException: org.hibernate.PersistentObjectException: detached entity passed to persist: *.Task; nested exception is javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist: *.Task
...
profileRepo.save() 应该能够处理任务列表的插入和更新。有没有一种优雅的方式来解决这个问题?