休眠：java.lang.ClassCastException：java.lang.Integer 不能转换为 java.lang.Double
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Hibernate : java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Double
提问by Amitab Das
My Staff Entity defined in Java is like this :
我在 Java 中定义的 Staff 实体是这样的：
final public class Staff {
private int staffId;
private String firstName = null;
private String lastName = null;
private String Email = null;
private double salary;
//and the setters and getters
}
My Query code :
我的查询代码：
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
Staff staff = null;
try {
Criteria criteria = session.createCriteria(dto.Staff.class);
criteria.add(Restrictions.eq("salary", 1000000));
staff = (Staff) criteria.uniqueResult();
} catch(Exception e) {
System.out.println("Error : " + e);
} finally {
session.close();
}
But when I run this I get an error which says :
但是当我运行它时，我收到一个错误消息：
java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Double
If I explicitly cast the number to a double it works :
如果我明确地将数字转换为双精度，它会起作用：
criteria.add(Restrictions.eq("salary", (double) 1000000));
Is there any way to do this without the explicit casting? Also I thought that in Java, Integer to Double conversion was Implicit?
有没有办法在没有显式转换的情况下做到这一点？我还认为在 Java 中，Integer 到 Double 的转换是隐式的？
采纳答案by Suresh Atta
Hibernate considering it as a integer, tell that it's double.
Hibernate 认为它是一个整数，告诉它是双精度的。
criteria.add(Restrictions.eq("salary", 1000000d));
回答by Scary Wombat
The restriction.eq takes an object, so no implicit casting is possible.
限制.eq 接受一个对象，因此不可能进行隐式转换。
