hibernate错误示例一

实体类:

@Entity
public class Cup {
@Id
@GeneratedValue(strategy=GenerationType.SEQUENCE)
private Long id;
private String name;

public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

//save方法:

Configuration conf=new AnnotationConfiguration().configure();
SessionFactory sf=conf.buildSessionFactory();
Session session=sf.getCurrentSession();
Transaction tx=session.beginTransaction();
Cup cup=new Cup();
cup.setName("yang");
Long l=(Long)session.save(cup);
tx.commit();
System.out.println(l);

result:l;

错误说明:

开始使用 int l=(Integer)session.save(cup);

运行程序时出现了如下错误:

运行的时候报这种错:java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer
因为Id的类型为Long型,Long l=(Long)session.save(cup);结果貌似是插入的数据列id的值,所以用int l =(Integer)session.save(cup)去接返回的值的时候会报上面的错误!

大家一定要警醒啊,找了整整一下午才！