hibernate 中使用 dual 求助

Question

请各位帮忙看看，谢谢
Dual.java
package bean;
import java.io.Serializable;
public class Dual implements Serializable {
private Long id;
public Long getId() {
return this.id;
}
public void setId(Long id) {
this.id = id;
}
}Dual.hbm.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="bean.Dual" table="DUAL">
<id name="id" type="java.lang.Long" column="ID">
<generator class="sequence"><!--可以替换-->
<param name="sequence">seq_flow</param>
</generator>
</id>
</class>
</hibernate-mapping>执行select seq_flow.nextval from Dual 这条语句时报错，次句在sqlplus正常执行
错误信息如下：org.hibernate.hql.ast.QuerySyntaxError: Invalid path: 'seq_flow.nextval' [select seq_flow.nextval from bean.Dual]
at org.hibernate.hql.ast.ErrorCounter.throwQueryException(ErrorCounter.java:63)
at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:196)
at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:130)
at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:83)
at org.hibernate.impl.SessionFactoryImpl.getQuery(SessionFactoryImpl.java:427)
at org.hibernate.impl.SessionImpl.getQueries(SessionImpl.java:884)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:834)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:74)
at DAO.LogicDAO.getSeq(LogicDAO.java:106)
at logic.impl.Logic.getSeq(Logic.java:46)
at web.LogicAction.gotoApplyQues(LogicAction.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:274)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:194)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at base.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:63)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:595)

Answer 1

你是用hql语句形式查询的么...把代码发来看看..

Answer 2

String sql="select seq_flow.nextval from Dual";
Session session = getFactory().openSession();
Object obj=null;
try{
Query query=session.createQuery(sql);
List list=query.list();
if(list.size()>0){
obj=list.get(0);
}
}catch(Exception e){
session.close();
e.printStackTrace();
return null;
}
System.out.println("seq..."+(String)obj);
 return (String)obj;

Answer 3

String sql="from Dual"; 这样可以么...

Answer 4

<generator class="sequence"><!--可以替换-->
<param name="sequence">seq_flow</param>
我不知道你这么做的用意时什么...所以...

Answer 5

没时间搞了，只能先用jdbc加上了，谢谢你