Question

我在下面发布了两个hibernate类，我试图使用populateAuthorTable方法中提到的代码将记录插入到TestAuthor表中，该方法也在下面发布。当我运行我收到的代码时

detached entity passed to persist: msc.hibernate.persistence.TestAuthor

请让我知道如何解决此错误

populateAuthorTable ：

private void populateAuthorTable() {
    // TODO Auto-generated method stub
    Session session = HibernateUtil.getCurrentSession();
    Transaction transaction = session.beginTransaction();
    ArrayList<TestAuthor> authorsList = new ArrayList<>();

    for (Long i = (long) 0; i < 30; i++) {
        authorsList.add(new TestAuthor(i, "FName_" + i, "LName_" + i));
    }

    int i = 0;
    for (TestAuthor ta : authorsList) {
        session.persist(ta);
        i++;
    }
}

TestAuthor ：

@Entity 
@Table(schema = "afk_owner", name = "testauthor")
public class TestAuthor {

@Id
@Column(name = "authorid")
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequencegen")
@SequenceGenerator(name = "sequencegen", sequenceName = "afk_owner.testauthor_seq", allocationSize = 1)
private Long mAuthorID;

@Column(name = "FNAME")
private String mFName;

@Column(name = "LNAME")
private String mLName;

@OneToMany(mappedBy = "author", cascade = CascadeType.ALL)
private List<TestBook> booksList;

public Long getmAuthorID() {
    return mAuthorID;
}

public List<TestBook> getBooksList() {
    return booksList;
}

public void setBooksList(List<TestBook> booksList) {
    this.booksList = booksList;
}

public void setmAuthorID(Long mAuthorID) {
    this.mAuthorID = mAuthorID;
}

public String getmFName() {
    return mFName;
}

public void setmFName(String mFName) {
    this.mFName = mFName;
}

public String getmLName() {
    return mLName;
}

public void setmLName(String mLName) {
    this.mLName = mLName;
}

public TestAuthor() {
}

public TestAuthor(Long id, String fName, String lName) {
    this.mAuthorID = id;
    this.mFName = fName;
    this.mLName = lName;
    this.booksList = new ArrayList<>();
}

}

Answer 1

当你设置一个新对象的@Id字段时，hibernate会认为它是一个独立的实体。您创建的序列生成器的要点是为新实体生成ID。只是没有设置ID，它应该工作。非常粗略的解决方案：

public TestAuthor(Long id, String fName, String lName) {
    //this.mAuthorID = id;
    this.mFName = fName;
    this.mLName = lName;
    this.booksList = new ArrayList<>();
}

通常，当您的对象真正分离时，您会收到此错误，而不仅仅是错误地启动了新对象。

持久化会话导致传递的分离实体持续存在错误

1 个答案: