Java 对于两个类/表之间的连接，正确的Hibernate查询语法是什么？
我已经做了几个小时，但没有成功。对于我从这里记录的其他事件或其他地方的示例中尝试的一切，HQL语法在我的方法中似乎总是错误的：Java 对于两个类/表之间的连接，正确的Hibernate查询语法是什么？,java,hibernate,hql,Java,Hibernate,Hql,我已经做了几个小时，但没有成功。对于我从这里记录的其他事件或其他地方的示例中尝试的一切，HQL语法在我的方法中似乎总是错误的： Session session = sessionFactory.openSession(); try { Query query = session.createQuery("select p from Person p join p.books where p.personId = :personId").setParameter("
Session session = sessionFactory.openSession();
try {
Query query = session.createQuery("select p from Person p join p.books where p.personId = :personId").setParameter("personId", personId);
List<Person> persons = query.list();
Person person = persons.get(0);
Hibernate.initialize(person.getBooks());
return person;
}
finally {
session.close();
}
select person0_.PERSON_ID as PERSON_I1_1_0_, book2_.BOOK_ID as BOOK_ID1_0_1_, person0_.ADDRESS as ADDRESS2_1_0_, person0_.EMAIL as EMAIL3_1_0_, person0_.NAME as NAME4_1_0_, person0_.TELEPHONE as TELEPHON5_1_0_, book2_.AUTHOR as AUTHOR2_0_1_, book2_.DESCRIPTION as DESCRIPT3_0_1_, book2_.ONLOAN as ONLOAN4_0_1_, book2_.person_Id as person_I6_0_1_, book2_.TITLE as TITLE5_0_1_, books1_.PERSON_PERSON_ID as PERSON_P1_1_0__, books1_.books_BOOK_ID as books_BO2_2_0__ from PERSON person0_ left outer join PERSON_BOOK books1_ on person0_.PERSON_ID=books1_.PERSON_PERSON_ID left outer join BOOK book2_ on books1_.books_BOOK_ID=book2_.BOOK_ID where person0_.PERSON_ID=?
Query query = session.createQuery("select from Person as p left join fetch p.books where p.personId = :personId").setParameter("personId", personId);
Your page request has caused a QuerySyntaxException: unexpected token: from near line 1, column 8 [select from library.model.Person as p left join fetch p.books where p.personId = :personId] error:
FROM Person as p LEFT JOIN FETCH p.books WHERE p.personId = :personId
如果您只是尝试在一个人内获取书籍，则不需要使用JOIN子句，只需加载Person对象将缓慢地获取他们的相关书籍，或者至少这是我通常的工作方式。不幸的是，每当我尝试从数据库中检索书籍之前，我都会收到一条与会话已关闭有关的消息。啊，这是因为它是惰性获取的，所以您需要将惰性获取更改为急切获取。懒洋洋地去拿我
Your page request has caused a QuerySyntaxException: unexpected token: from near line 1, column 8 [select from library.model.Person as p left join fetch p.books where p.personId = :personId] error:
org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:91)
FROM Person as p LEFT JOIN FETCH p.books WHERE p.personId = :personId