Hibernate LeftOuter join HQL

问题

This is my left join hql query. After executing this code i am getting list size. But unable cast object to respective pojo class.

Query query=session.createQuery("from BwClientdetails client left join client.bwClientAllocations");

System.out.println(">>>"+query.list().size());
List<BwClientdetails> list=query.list();
for(int i=0;i<list.size();i++){
   BwClientdetails bc=list.get(i);
   System.out.println(bc.getClientid());
}

I am getting below error:

java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to org.bluewhale.model.BwClientdetails
        at testapplication.Main.getClients(Main.java:364)
        at testapplication.Main.main(Main.java:54)

回答1:

By not specifing a Select case, the result of your query is an Array of BwClientdetails, bwClientAllocations. Adding Select client in front of the query should solve your problem

Select client from  BwClientdetails  client left  join client.bwClientAllocations

or replacing your for by

for(int i=0;i<list.size();i++){
   BwClientdetails bc=list.get(i)[0];
   System.out.println(bc.getClientid());
}

It's a best practice to alway specify a where clause, it is even part of the JPA spec

来源：https://stackoverflow.com/questions/5922768/hibernate-leftouter-join-hql