我有一个Web应用程序,该应用程序具有搜索表单,并且HQL是即时生成的。此外,用户可以单击列标题以根据需要对项目进行排序。一些列从非常深的结构中获取其他数据。
例如,我有这个HQL,它可以完美地工作:
SELECT s FROM Application s LEFT JOIN s.product AS product LEFT JOIN product.originCountry AS origin WHERE s.nr = ? ORDER BY origin.name ASC
但是这一失败惨败:
SELECT s FROM Application s LEFT JOIN s.product AS product LEFT JOIN product.producer AS producer LEFT JOIN producer.address AS address LEFT JOIN address.country AS country WHERE s.nr = ? ORDER BY country.name ASC
有人可以指出,我要去哪里错了。不支持这种深层语法吗?
hibernate版本是3.2.1。
抱歉,忘记了堆栈跟踪:
2012-04-04 18:59:42,198 ERROR [foo.impl.ServiceImpl] java.lang.NullPointerException java.lang.NullPointerException at org.hibernate.hql.ast.HqlSqlWalker.createFromJoinElement(HqlSqlWalker.java:312) at org.hibernate.hql.antlr.HqlSqlBaseWalker.joinElement(HqlSqlBaseWalker.java:3275) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3067) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:2945) at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:688) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:544) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:281) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:229) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:228) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:160) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:111) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:77) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:56) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:72) at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:133) at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:112) at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1623) at sun.reflect.GeneratedMethodAccessor336.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.springframework.orm.hibernate3.HibernateTemplate$CloseSuppressingInvocationHandler.invoke(HibernateTemplate.java:1192) at $Proxy90.createQuery(Unknown Source) .....
正如@JBNizet正确指出的那样,问题是address路径上的一个类(确切地说是名称)不是实体,它是可嵌入的对象,因此不需要联接。
address
因此在我的情况下正确编写的第二个查询将是:
SELECT s FROM Application s LEFT JOIN s.product AS product LEFT JOIN product.producer AS producer LEFT JOIN producer.address.country AS country WHERE s.nr = ? ORDER BY country.name ASC