HQL - join fetch在子节点中设置父实体

Question

我有两个实体

public class Invoice {
    @Id
    @GeneratedValue
    @Column(name = "id_invoice")
    private long id;

    @OneToMany(mappedBy = "invoice", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    private List<InvoiceLine> invoiceLineList;
}

和

public class InvoiceLine {
    @Id
    @GeneratedValue
    @Column(name = "id_invoice_line")
    private long id;

    @ManyToOne(fetch = FetchType.LAZY)
    private Invoice invoice;
}

我有一个HQL查询用户，用于检索带有相关发票行的发票

SELECT i FROM Invoice as i left outer join fetch i.invoiceLineList as invoiceLines WHERE i.id=(:id)

正确检索发票，但问题是在发票行列表中，对象＆＃34;发票＆＃34;已设定。这是一个很大的问题，因为我有一个序列化此发票的方法，它返回StackOverflow例外（发票 - ＆gt; invoiceLine - ＆gt;发票 - ＆gt; invoiceLine - ＆gt; ...）

如何避免这个父实体集？