休眠子查詢拋出空指針異常

我想火從休眠子查詢，但它顯示NPE :-(任何人都知道如何解決它的下面是代碼：休眠子查詢拋出空指針異常

DetachedCriteria criteria = DetachedCriteria.forClass(My.class,"A"); 
     criteria.createAlias("A.a", "a"); 
     criteria.createAlias("A.b", "b"); 
     if(cValue !=null && cValue.size()>0){ 
      criteria.add(Restrictions.in("b.c", cValue)); 
     } 
     if(StringUtils.isNotEmpty(commodityList)){ 
      DetachedCriteria commCriteria = DetachedCriteria.forClass(My.class,"A1"); 
      commCriteria.createAlias("A1.a", "a1"); 
      commCriteria.add(Restrictions.in("a1.name", commodityList.split(","))); 
      criteria.add(Subqueries.propertyIn("b.c", commCriteria)); 
     } 
     criteria.addOrder(Order.asc("b.c")); 

     return getHibernateTemplate().findByCriteria(criteria);

堆棧跟蹤：

java.lang.NullPointerException 
    at org.hibernate.loader.criteria.CriteriaQueryTranslator.getProjectedTypes(CriteriaQueryTranslator.java:318) 
    at org.hibernate.criterion.SubqueryExpression.toSqlString(SubqueryExpression.java:56) 
    at org.hibernate.loader.criteria.CriteriaQueryTranslator.getWhereCondition(CriteriaQueryTranslator.java:334) 
    at org.hibernate.loader.criteria.CriteriaJoinWalker.<init>(CriteriaJoinWalker.java:82) 
    at org.hibernate.loader.criteria.CriteriaLoader.<init>(CriteriaLoader.java:67) 
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1550) 
    at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283) 
    at org.springframework.orm.hibernate3.HibernateTemplate$36.doInHibernate(HibernateTemplate.java:1065) 
    at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:419) 
    at org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374) 
    at org.springframework.orm.hibernate3.HibernateTemplate.findByCriteria(HibernateTemplate.java:1055) 
    at org.springframework.orm.hibernate3.HibernateTemplate.findByCriteria(HibernateTemplate.java:1048) 
    at com.boeing.kmapi.base.skillset.dao.impl.EssSkillsetCommMapDAOImpl.getEssSkillsetCommMapforSkillsetIdList(EssSkillsetCommMapDAOImpl.java:51) 
    at com.boeing.kmapi.base.skillset.service.impl.EssGenericReportServiceImpl.filterCommodityDetails(EssGenericReportServiceImpl.java:87) 
    at com.boeing.kmapi.base.skillset.service.impl.EssGenericReportServiceImpl.getGenericReport(EssGenericReportServiceImpl.java:79) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597)

問題通過加入突起內部查詢原來決心。

commCriteria.createAlias("A1.b", "b1"); 
commCriteria.setProjection(Projections.projectionList().add(Projections.property("b1.c")));

來源

2013-03-26 Renjith

發佈stacktrace並顯示至少拋出NPE的行。你試圖調試什麼？ – 2013-03-26 06:26:38

如果解決了問題，請將解決問題的2行作爲此問題的答案發布，然後將其標記爲接受的答案 – 2013-03-26 08:51:23

問題被原來決心b y將投影添加到內部查詢中。

commCriteria.createAlias("A1.b", "b1"); 
commCriteria.setProjection(Projections.projectionList().add(Projections.property("b1.c")));

來源

2013-03-26 09:09:26 Renjith

休眠子查詢拋出空指針異常

回答

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