java.lang.ClassCastException：[Ljava.lang.Object;不能转换为className

本文介绍了java.lang.ClassCastException：[Ljava.lang.Object;不能转换为className的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 代码：

public void getDetails（）{ try { Session session = sessionFactory.openSession（）; Transaction transaction = session.beginTransaction（）; String hql =select c.mobile，c.password FROM CrbtSubMasterDemo c where rownum< 20; Query query = session.createQuery（hql）; 列表< CrbtSubMasterDemo> itr = query.list（）; session.getTransaction（）。commit（）; for（CrbtSubMasterDemo pojo：itr）{// excepion line System.out.println（[+ pojo.getMobile（）+]）; } } catch（Exception e）{ e.printStackTrace（）;

CrbtSubMasterDemo 与数据库。 当我尝试运行它时，它会给出以下异常：

java.lang.ClassCastException：[Ljava.lang 。目的;无法转换为com.telemune.demoPojo.CrbtSubMasterDemo at com.telemune.demoHibernate.QueryTester.getDetails（QueryTester.java:57） at com.telemune.demoHibernate.QueryTester.main（QueryTester.java ：23）

问题是query.list（）返回pojo类的对象列表。那么为什么是这个例外。我是Hibernate的新手，对不起，如果它是一个愚蠢的问题。解决方案

主席先生，很多时候用户面临这种需求。 Hibernate有ResultTransformer来转换Object中的hql / sql。

public CrbtSubMasterDemo { private Stirng mobile; 私人字符串密码; public CrbtSubMasterDemo（）{ -------------- } ##### after设置转换集合，无论你选择哪一列应该作为你的对象的属性名称给出 String hql =select c.mobile as mobile，c.password as password FROM CrbtSubMasterDemo c where rownum< 20; Query query = session.createQuery（hql）; 列表< CrbtSubMasterDemo> itr = query.setResultTransformer（Transformers.aliasToBean（CrbtSubMasterDemo.class））.list（）; ##无需提交交易。 }

它会将您的查询转换为CrbtSubMasterDemo

Code:

public void getDetails() { try { Session session = sessionFactory.openSession(); Transaction transaction = session.beginTransaction(); String hql = "select c.mobile, c.password FROM CrbtSubMasterDemo c where rownum<20"; Query query = session.createQuery(hql); List<CrbtSubMasterDemo> itr = query.list(); session.getTransaction()mit(); for (CrbtSubMasterDemo pojo : itr) {//excepion line System.out.println("[" + pojo.getMobile() + "]"); } } catch (Exception e) { e.printStackTrace(); } }

CrbtSubMasterDemo is pojo mapped with the db. When I try to run it, it gives following Exception:

java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.telemune.demoPojo.CrbtSubMasterDemo at com.telemune.demoHibernate.QueryTester.getDetails(QueryTester.java:57) at com.telemune.demoHibernate.QueryTester.main(QueryTester.java:23)

The question is query.list() is returning the list of objects of pojo class. Then why is this Exception. I am new to Hibernate, sorry if its a silly question.

解决方案

Sir, Many times user faces this kinda requirements . Hibernate has ResultTransformer to convert a hql/sql in Object.

public CrbtSubMasterDemo{ private Stirng mobile; private String password; public CrbtSubMasterDemo(){ -------------- } #####after setting the transation set whichever columns you are selecting should be given as name of property of your object String hql = "select c.mobile as mobile, c.password as password FROM CrbtSubMasterDemo c where rownum<20"; Query query = session.createQuery(hql); List<CrbtSubMasterDemo> itr = query.setResultTransformer(Transformers.aliasToBean(CrbtSubMasterDemo.class) ).list(); ##No need to commit the transaction. }

It will convert you query into the CrbtSubMasterDemo