使用join fetch with JPA2 CriteriaQuery的简单例子

protected TypedQuery getCriteriaQuery(SearchType searchType,SearchCriteria searchCriteria){
    CriteriaBuilder cb=histDao.getEntityManager().getCriteriaBuilder();
    CriteriaQuery cq=cb.createQuery(RequestInfo.class);
//  Metamodel m=histDao.getEntityManager().getMetamodel();
//  EntityType RequestInfo_=m.entity(RequestInfo.class);
    Root from=cq.from(RequestInfo.class);
    EntityType RequestInfo_=from.getModel();
    Join join1=from.join(RequestInfo_.getSingularAttribute("batchInfo", BatchInfo.class), JoinType.INNER);
    Join join2=from.join(RequestInfo_.getSet("portInfo", PortInfo.class), JoinType.LEFT);
    from.fetch(RequestInfo_.getSet("portInfo"), JoinType.LEFT);
    cq.select(from);
    cq.where(cb.equal(from.get(RequestInfo_.getSingularAttribute("requestId", String.class)),"CE.0010650337_D"));

    TypedQuery typedQuery=histDao.getEntityManager().createQuery(cq);
    return typedQuery;
    }