java.lang.ClassCastException：[Ljava.lang.Object; 不能强制转换为className

一尘不染

java.lang.ClassCastException：[Ljava.lang.Object; 不能强制转换为className

hibernate

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);
List<CrbtSubMasterDemo> itr = query.list();
session.getTransaction().commit();
for (CrbtSubMasterDemo pojo : itr) {//excepion line
System.out.println("[" + pojo.getMobile() + "]");
}
} catch (Exception e) {
e.printStackTrace();
}
}

CrbtSubMasterDemo 与数据库一起映射。当我尝试运行它时，它显示以下异常：

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)

问题是query.list（）返回pojo类的对象列表。那为什么是这个异常。我是Hibernate的新手，很抱歉这是一个愚蠢的问题。

阅读 357

2020-06-20

共1个答案

一尘不染

先生，许多用户都面临这种需求。Hibernate具有ResultTransformer来在Object中转换hql / sql。

    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.
    }

它将您查询转换为CrbtSubMasterDemo

2020-06-20