Object 转int 缺报 long 不能转int的错误

Question

String jpql="select count(t) from student t";
Query
query=entityManager.createQuery(jpql); Object sum= query.getSingleResult();
pg.setSum((int)sum);

pg.setSum((int)sum);他说我这句ava.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer

Answer 1

Object sum= query.getSingleResult(); 这里返回的是Long类型的，所以你转成Long类型就好了
pg.setSum((Long)sum);