ssh

[xiangdeweiwangfengg]

ssh简单问题：调用NewsDAO里面操作数据库的方法出错，
简单描述一下我的相关代码：

NewsAction:
public class NewsAction extends DispatchAction {

//删除信息
public ActionForward deleteNews(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {

String nids[] = request.getParameterValues("nid");
int cid = -1;
int nid = Integer.parseInt(nids[0]);
newsDao.findNewByNid(nid);
............
applicationContext.xml

<bean name="/news" class="com.aso.struts.action.NewsAction"
abstract="false" lazy-init="default" autowire="default"
dependency-check="default">
<property name="newsDao">
<ref bean="NewsDAO" />
</property>
<property name="newsPaging">
<ref bean="NewsPaging" />
</property>
</bean>

NewsDAO:
public News findNewByNid(int nid)
{
log.debug("getting News instance with nid");
try {
News instance = (News) getHibernateTemplate().find("from News as news where news.nid="+nid);
return instance;
} catch (RuntimeException re) {
log.error("get failed", re);
throw re;
}
}

---------------------运行报错位置------------------------
newsDao.findNewByNid(nid);

---------------------报错信息----------------------------

严重: Servlet.service() for servlet action threw exception
java.lang.ClassCastException: java.lang.String
at org.hibernate.type.TimestampType.isEqual(TimestampType.java:77)
at org.hibernate.type.NullableType.isEqual(NullableType.java:160)
at org.hibernate.type.AbstractType.isSame(AbstractType.java:104)
at org.hibernate.type.AbstractType.isDirty(AbstractType.java:70)
at org.hibernate.type.NullableType.isDirty(NullableType.java:186)
at org.hibernate.type.TypeFactory.findDirty(TypeFactory.java:476)
at org.hibernate.persister.entity.AbstractEntityPersister.findDirty(AbstractEntityPersister.java:2803)
at org.hibernate.event.def.DefaultFlushEntityEventListener.dirtyCheck(DefaultFlushEntityEventListener.java:467)
at org.hibernate.event.def.DefaultFlushEntityEventListener.isUpdateNecessary(DefaultFlushEntityEventListener.java:190)
at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:113)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:195)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:76)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:26)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:985)
at org.springframework.orm.hibernate3.HibernateAccessor.flushIfNecessary(HibernateAccessor.java:390)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:373)
at org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:840)
at org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:836)
at com.aso.dao.NewsDAO.findByProperty(NewsDAO.java:92)
at com.aso.dao.NewsDAO.findByWriter(NewsDAO.java:104)
at com.aso.struts.action.NewsAction.deleteNews(NewsAction.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:270)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187)
at org.apache.struts.actions.LookupDispatchAction.execute(LookupDispatchAction.java:150)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)


我是自学SSH的，昨天遇到这个问题，想了很久都不知道哪儿错了，请指教

[Landor2004]

News 里面的属性的类型和数据库是对应的吗，检查一下，数据库是datetime类型的话，News 里面应该是Date类型

[xiangdeweiwangfengg]

[Quote=引用 2 楼 Landor2004 的回复:]
News 里面的属性的类型和数据库是对应的吗，检查一下，数据库是datetime类型的话，News 里面应该是Date类型
[/Quote]

---------------------------------------------------------

应该是对的，我是用Hibernate Reverse Engineering 一对一的根据数据库表的字段叛向工程的，
肯定没问题

[xiangdeweiwangfengg]

public class News implements java.io.Serializable {

// Fields

private Integer nid;
private Ncategory ncategory;
private String ntitle;
private String writer;
private String imgPath;
private String content;
private Date issueTime;
private Integer pcId;
private Integer ncount;
......
问题不是在这里，不过仍然谢谢您

[xiangdeweiwangfengg]

我再更正一下错误：
at com.aso.dao.NewsDAO.findByWriter(NewsDAO.java:104)
at com.aso.struts.action.NewsAction.deleteNews(NewsAction.java:74)

-->

at com.aso.dao.NewsDAO.findNewByNid(NewsDAO.java:104)
at com.aso.struts.action.NewsAction.deleteNews(NewsAction.java:74)

刚才发贴的时候该了一下

[B1977]

你连的是什么数据库,有的数据库的语句不用as 意思是说form News n where ..... 还有你最好不要把News news这样写如果不区分大小写的话那不是一样了??

[xiangdeweiwangfengg]

[Quote=引用 6 楼 zhengbr 的回复:]
你连的是什么数据库,有的数据库的语句不用as 意思是说form News n where ..... 还有你最好不要把News news这样写如果不区分大小写的话那不是一样了??
[/Quote]

--------------------我用的是sqlserver数据库-----------------------------------------

[xiangdeweiwangfengg]

sqlserver可以这样用的。

[xiaoxiasiemens]

天天在想怎么样才能不做程序员

[gongyali2005]

java.lang.ClassCastException: java.lang.String //类型转换了？
News instance = (News) getHibernateTemplate().find("from News as news where news.nid="+nid);
这句换成SESSION试试。

[watermarkmms]

News instance = (News) getHibernateTemplate().find("from News as news where news.nid="+nid);
????????

getHibernateTemplate().find("from News as news where news.nid="+nid);
返回单个对象？？？就算是单个对象，也应该是用(News)(getHibernateTemplate().find("from News as news where news.nid="+nid).get(0))这样来取的吧？？？