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java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer

热度:11   发布时间:2023-12-13 06:05:46.0
异常信息:

java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer


由于Hibernate3.2.5版本的(select count(*))查询返回的结果是个Long 不能强制转换:

public int getAllUserNum(){
Session session = HiberSF.getSession();
try {
session.getTransaction().begin();

Long lo = (Long)session.createQuery("select count(*) from User").uniqueResult();
//解决办法把long型拆分字符串进行转换
Integer sum = new Integer(String.valueOf(lo));
session.getTransaction().commit();
return sum;
} catch (RuntimeException e) {
session.getTransaction().rollback();
throw e;
// TODO: handle exception
} finally {
session.close();
}
}




第二种办法:

public int getAllUserNum(){
Session session = HiberSF.getSession();
try {
session.getTransaction().begin();
//解决办法直接调用:HashCode();
//count(*)也可以理解为返回一个Object的对象,然后直接
//调用 hashCode();
Integer lo = (Integer)session.createQuery("select count(*) from User").uniqueResult().hashCode();
session.getTransaction().commit();
return sum;
} catch (RuntimeException e) {
session.getTransaction().rollback();
throw e;
// TODO: handle exception
} finally {
session.close();
}
}