hibernate 调用save()方法时异常 什么原因啊

Question

Hibernate: select hibernate_sequence.nextval from dual
java.lang.ClassCastException: java.lang.String
        at net.sf.hibernate.type.TimestampType.deepCopyNotNull(TimestampType.java:63)
        at net.sf.hibernate.type.NullableType.deepCopy(NullableType.java:96)
        at net.sf.hibernate.type.TypeFactory.deepCopy(TypeFactory.java:212)
        at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:937)
        at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:868)
        at net.sf.hibernate.impl.SessionImpl.saveWithGeneratedIdentifier(SessionImpl.java:790)
        at net.sf.hibernate.impl.SessionImpl.save(SessionImpl.java:749)
        at org.springframework.orm.hibernate.HibernateTemplate$9.doInHibernate(HibernateTemplate.java:555)
        at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:363)
        at org.springframework.orm.hibernate.HibernateTemplate.save(HibernateTemplate.java:552)
        at com.viewtoo.podcasting.user.comment.CommentDataAccessImpl.addAssetComment(CommentDataAccessImpl.java:159)
        at com.viewtoo.podcasting.user.comment.CommentService.addComment(CommentService.java:181)
        at com.viewtoo.podcasting.servlet.CommentServlet.doPost(CommentServlet.java:134)
        at com.viewtoo.podcasting.servlet.CommentServlet.doGet(CommentServlet.java:38)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

Answer 1

类型转换错误
java.lang.ClassCastException: java.lang.String 

Answer 2

ClassCastException 是 两个类型间的转换不兼容时引发的运行时异常。把你的关键代码贴出来看看，

Answer 3

  不出意外的话是在dao现实层，把从数据库中取出的值强转成String了

Answer 4

  不出意外的话是在dao现实层，把从数据库中取出的值强转成String了

Answer 5

save时出现的异常？
比对下你的 映射类型 ~