一百分解决一个HIBERNATE简单问题
报错提示

Hibernate: select bulletin0_.id as x0_0_ from BULLETIN bulletin0_
java.lang.ClassCastException
  at meis.tag.Bulletin_tag.doAfterBody(Bulletin_tag.java:48)
  at jsp_servlet.__index._jspService(__index.java:202)
  at weblogic.servlet.jsp.JspBase.service(JspBase.java:33)
  at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run
(ServletStubImpl.java:1006)
  at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm



代码

Query query=session.createQuery("select b.id from meis.hibernate.Bulletin as b");
 
java.util.List list=query.list();

result.append("<TABLE width=\"97%\" border=\"0\" cellspacing=\"6\" cellpadding=\"0\"><tr><td>dfdsfsdf"+list.size()+"</td></tr>");

Iterator iter = list.iterator();

while (iter.hasNext()) 
{
.....
}
/*
*/



映射类文件
package meis.hibernate;

public class Bulletin {


//发布日期

private String id;

private String issuedate;
private String title;

public String getId()
{ 
return id; 
} 
public void setId(String id) 
{ 
this.id = id; 
}

public String getIssuedate()
{ 
return issuedate; 
} 

public void setIssuedate(String issuedate) 
{ 
this.issuedate = issuedate; 
} 

public String getTitle()
{ 
return title; 
} 
public void setTitle(String title) 
{ 
this.title = title; 
}

}

配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
  <class name="meis.hibernate.Bulletin" table="BULLETIN">
  <id name="id">
  <generator class="assigned" />
  </id>
  <property name="issuedate" /> 
  <property name="title" /> 
  </class> 

</hibernate-mapping>


------解决方案--------------------
while (iter.hasNext()) 
{
.....
} 
把其中的内容发上来
------解决方案--------------------
用数组来解决吧

Object[] bulletin= (Object[]) iter.next(); 

bulletin[0]

bulletin[1]
------解决方案--------------------
meis.hibernate.Bulletin bulletin=(meis.hibernate.Bulletin)iter.next(); 
转型错误
------解决方案--------------------
Query query=session.createQuery("select b.id from meis.hibernate.Bulletin as b");
java.util.List list=query.list(); 中返回的不是Bulletin对象
好好对比一下!
------解决方案--------------------
karlpan01 说到：
Query query=session.createQuery("select b.id from meis.hibernate.Bulletin as b");
java.util.List list=query.list(); 中返回的不是Bulletin对象
好好对比一下!

就是这个答案了。你的list里面现在放的是一些id,比如{1，2，3，4}，

而不是bulletin的对象{bulletin1,bulletin2,bulletin3,bulletin4}.