我正在尝试使用单个命名查询来获取一组结果并计算可用数据量。我有一个命名的JPQL查询：
@NamedQuery(name = "query.all.absences.by.name", query = "SELECT a FROM Absence a WHERE a.name = :name")
当我获得缺勤时，我将像这样调用查询：
final Query q = em.createNamedQuery("query.all.absences.by.name");
q.setParameter("name","aRandomAbsenceName");
//maxResults and firstResult are coming as parameters, are computed in another method
q.setMaxResults(maxResults);
q.setFirstResult(firstResult);
q.getResultList()为我提供正确的结果集。到现在为止还挺好。现在，我要做的是使用相同的命名查询来执行计数查询。
我正在执行以下操作：
final Query q = em.createNamedQuery("query.all.absences.by.name");
q.setParameter("name","aRandomAbsenceName");
q.setHint(QueryHints.QUERY_TYPE, "org.eclipse.persistence.queries.ReportQuery");
final ReportQuery test = JpaHelper.getReportQuery(q);
test.addCount();
test.setShouldReturnWithoutReportQueryResult(true);
如果我的命名查询没有参数，则此方法效果很好。但是使用参数时，如果我执行上面定义的ReportQuery，则有以下异常：
Exception [EclipseLink-6094] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.QueryException
Exception Description: The parameter name [name] in the query's selection criteria does not match any parameter name defined in the query.
Query: ReportQuery(referenceClass=AbsenceCategory sql="SELECT COUNT(CATEGORY_KEY) FROM ABSENCE_CATEGORY WHERE (CATEGORY_KEY = ?)")
at org.eclipse.persistence.exceptions.QueryException.parameterNameMismatch(QueryException.java:1063)
at org.eclipse.persistence.internal.expressions.ParameterExpression.getValue(ParameterExpression.java:275)
at org.eclipse.persistence.internal.databaseaccess.DatabaseCall.translate(DatabaseCall.java:1000)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:206)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:193)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeSelectCall(DatasourceCallQueryMechanism.java:264)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.selectAllRows(DatasourceCallQueryMechanism.java:646)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRowsFromTable(ExpressionQueryMechanism.java:2611)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllReportQueryRows(ExpressionQueryMechanism.java:2554)
at org.eclipse.persistence.queries.ReportQuery.executeDatabaseQuery(ReportQuery.java:846)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:844)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1040)
at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:392)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1128)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2871)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1516)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1498)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1449)
我还能如何将参数设置为ReportQuery？
我正在使用EclipseLink 2.0。
最佳答案
您如何执行ReportQuery？您需要调用Session.executeQuery（query，arguments）并传递参数列表（顺序与query.getArguments（）相同）。
您可能还可以使用JpaEntityManager createQuery（DatabaseQuery）API将ReportQuery转换回JPA查询，然后就可以以JPA方式设置参数。