SSH 查找时出现java.lang.IllegalArgumentException异常

很诡异的异常 现在可以确定报错函数传参没问题，vo和hibernate映射也没问题，并且查另一个VO用同样的方式没有报错，郁闷，求助高手！下面是异常信息：
2:42:26,106 ERROR [default]:253 - Servlet.service() for servlet default threw exception
java.lang.IllegalArgumentException
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)
at org.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:42)
at org.hibernate.tuple.entity.AbstractEntityTuplizer.setPropertyValues(AbstractEntityTuplizer.java:337)
at org.hibernate.tuple.entity.PojoEntityTuplizer.setPropertyValues(PojoEntityTuplizer.java:200)
at org.hibernate.persister.entity.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:3571)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:133)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:854)
at org.hibernate.loader.Loader.doQuery(Loader.java:729)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.doList(Loader.java:2213)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
at org.hibernate.loader.Loader.list(Loader.java:2099)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:378)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:338)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1121)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at cn.sl.dao.imp.AddressDaoImp.findDistrict(AddressDaoImp.java:16)//我写的方法
//报错语句：List<District> list=this.getSession().createQuery("from District d where d.city.cId="+cityId).list();
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)

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