带有列表的JPA CriteriaQuery投影

Question

我试图使用包装类作为结果类型进行查询。很抱歉，这篇较长的文章，但我想尽可能地完成我的问题。 根类有3只列出了我要检索：

@Entity 
@Table(name = "cash") 
public final class Cash extends BaseSimpleModel { 
    @Id 
    @SequenceGenerator(name = "id", sequenceName = "cash_seq") 
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "id") 
    private Long cashID; 

    @Column(length = 50, unique = true) 
    private String description; 

    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true) 
    @JoinColumn(name = "cashID") 
    private List<CashAllowedValue> allowedValueList; 

    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true) 
    @JoinColumn(name = "cashID") 
    private List<CashAllowedCurrency> allowedCurrencyList; 

    @OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true) 
    @JoinColumn(name = "cashID") 
    private List<CashAllowedCashier> allowedCashierList; 
    ... getters and setters 
} 

这里是我的包装类：

public class CashQueryResult extends QueryResult { 
    private Long cashID; 
    private String description; 
    private List<CashAllowedValue> allowedValueList; 
    private List<CashAllowedCurrency> allowedCurrencyList; 
    private List<CashAllowedCashier> allowedCashierList; 

    public CashQueryResult(Long id, String description, List<CashAllowedValue> allowedValueList, List<CashAllowedCurrency> allowedCurrencyList, List<CashAllowedCashier> allowedCashierList) 
    { 
     this.cashID = id; 
     this.description = description; 
     this.allowedValueList = allowedValueList; 
     this.allowedCurrencyList = allowedCurrencyList; 
     this.allowedCashierList = allowedCashierList; 
    } 
    ... getters 
} 

这里是我的查询：

public final List<CashQueryResult> getQRList(final CashQueryParameter cashQP, final QueryHint queryHint) { 
    List<CashQueryResult> cashQRL = null; 
    try { 
     final CriteriaBuilder cb = em.getCriteriaBuilder(); 
     final PredicateBuilder pb = new PredicateBuilder(cb); 
     final CriteriaQuery<CashQueryResult> cq = cb.createQuery(CashQueryResult.class); 
     final Root<Cash> cash = cq.from(getModelClass()); 

     // Joins. 
     final ListJoin<Cash, CashAllowedValue> allowedValueList = cash.join(Cash_.allowedValueList, JoinType.LEFT); 
     final ListJoin<Cash, CashAllowedCurrency> allowedCurrencyList = cash.join(Cash_.allowedCurrencyList, JoinType.LEFT); 
     final ListJoin<Cash, CashAllowedCashier> allowedCashierList = cash.join(Cash_.allowedCashierList, JoinType.LEFT); 

     // Paths. 
     final Path<ValueTypeEnum> valueType = allowedValueList.get(CashAllowedValue_.valueType); 
     final Path<Currency> currency = allowedCurrencyList.get(CashAllowedCurrency_.currency); 
     final Path<IntranetUser> intranetUser = allowedCashierList.get(CashAllowedCashier_.cashier); 

     // Expressions. Just for testing purposes. 
     final Expression<List<CashAllowedValue>> cashAllowedValueListExpression = cash.get(Cash_.allowedValueList); 
     final Expression<List<CashAllowedCurrency>> cashAllowedCurrencyExpression = cash.get(Cash_.allowedCurrencyList); 
     final Expression<List<CashAllowedCashier>> cashAllowedCashierExpression = cash.get(Cash_.allowedCashierList); 

     cq.distinct(true); 
     cq.select(cb.construct(CashQueryResult.class, cash.get(Cash_.cashID), cash.get(Cash_.description), 
      // cash.get(Cash_.allowedValueList), cash.get(Cash_.allowedCurrencyList), cash.get(Cash_.allowedCashierList) // does not work 
      // cashAllowedValueListExpression, cashAllowedCurrencyExpression, cashAllowedCashierExpression // does not work 
      allowedValueList, allowedCurrencyList, allowedCashierList // does not work 
     )); 

     // cq.multiselect(cash.get(Cash_.cashID), cash.get(Cash_.description), 
     //  allowedValueList, allowedCurrencyList, allowedCashierList 
     //); // does not work 

     cq.where(cb.and(pb.like(cash.get(Cash_.description), cashQP.getDescription()), pb.equal(valueType, cashQP.getValueType()), pb.equal(currency.get(Currency_.currencyID), cashQP.getCurrencyID()), pb.equal(intranetUser.get(IntranetUser_.agentID), cashQP.getIntranetUserID()))); 
     cq.orderBy(cb.asc(cash.get(Cash_.description))); 

     final TypedQuery<CashQueryResult> tq = em.createQuery(cq); 
     tq.setFirstResult(queryHint.getFirstResult()); 
     tq.setMaxResults(queryHint.getMaxResults()); 
     cashQRL = tq.getResultList(); 
    } 
    catch (Throwable t) { 
     throw new EJBException(t.getMessage()); 
    } 
    return cashQRL; 
} 

最后，异常（这取决于我尝试的选择方法，但总是这样）：

2011-09-12 16:12:26,165 ERROR [org.hibernate.hql.PARSER] (http-127.0.0.1-8080-2) Unable to locate appropriate constructor on class [com.ebizlink.adonis.erp.model.support.CashQueryResult] [cause=org.hibernate.PropertyNotFoundException: no appropriate constructor in class: com.ebizlink.adonis.erp.model.support.CashQueryResult] 
2011-09-12 16:12:26,169 SEVERE [javax.enterprise.resource.webcontainer.jsf.context] (http-127.0.0.1-8080-2) javax.ejb.EJBException: org.hibernate.hql.ast.QuerySyntaxException: 
Unable to locate appropriate constructor on class [com.ebizlink.adonis.erp.model.support.CashQueryResult] 
[select distinct new com.ebizlink.adonis.erp.model.support.CashQueryResult(generatedAlias0.cashID, generatedAlias0.description, generatedAlias1, generatedAlias2, generatedAlias3) 
from com.ebizlink.adonis.erp.model.Cash as generatedAlias0 
    left join generatedAlias0.allowedValueList as generatedAlias1 
    left join generatedAlias0.allowedCurrencyList as generatedAlias2 
    left join generatedAlias0.allowedCashierList as generatedAlias3 
where (1=1) and (1=1) and (1=1) and (1=1) 
order by generatedAlias0.description asc] 

仅供参考，以下是PredicateBuilder以防万一。 我搜索了网页，但我找不到想要检索多个列表的人。 我错过了一些明显的东西吗？多次提取是一个不行（休眠错误），我也不能使列表渴望。

另一个相关的问题是： 我可以做一个查询，以便我的包装类的列表也是实体包装而不是实体？ （例如：代替使用Cashiers，只需要名字和姓氏，并使用包含两个字符串的CashierWrapper列表）

我真的很感谢你，我希望你能帮助我。

Answer 1

很可能是你不能做，什么规格说，有关参数表达式构造：

constructor_expression :: = NEW constructor_name（constructor_item {，constructor_item} *） constructor_item :: = single_valued_pa​​th_expression |标量表达式|聚合表达式| identification_variable

您试图提供给构造函数的列表（collection_valued_field）不是constructor_item中的任何一个。