Hibernate Servlet出错，搞了几天了，求大神给看看

Question

 这个是错误信息：
org.hibernate.MappingException: could not instantiate id generator
at org.hibernate.id.IdentifierGeneratorFactory.create(IdentifierGeneratorFactory.java:98)
at org.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:152)
at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:192)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1294)
at jrdn.jcy.daoimpl.UserDaoImpl.checkUserLogin(UserDaoImpl.java:22)
at jrdn.jcy.action.UserAction.userLogin(UserAction.java:115)
at jrdn.jcy.action.UserAction.doPost(UserAction.java:78)
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 jrdn.jcy.util.EncodingFilter.doFilter(EncodingFilter.java:22)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
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:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)

Answer 1

这是映射：<?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">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="jrdn.jcy.vo.User" table="JCY_USER" schema="NET_TAX" catalog="jcy">
        <id name="username" type="java.lang.String">
            <column name="USERNAME" length="20" />
            <generator class="assigned"></generator>
        </id>
        <property name="dwbm" type="java.lang.String">
            <column name="DWBM" length="20" />
        </property>
        <property name="bmbm" type="java.lang.String">
            <column name="BMBM" length="20" />
        </property>
        <property name="password" type="java.lang.String">
            <column name="PASSWORD" length="32" />
        </property>
        <property name="mc" type="java.lang.String">
            <column name="MC" length="20" />
        </property>
        <property name="dhhm" type="java.lang.String">
            <column name="DHHM" length="20" />
        </property>
        <property name="sjhm" type="java.lang.String">
            <column name="SJHM" length="20" />
        </property>
        <property name="dlcs" type="java.lang.Integer">
            <column name="DLCS" precision="22" scale="0" />
        </property>
        <property name="zhdlsj" type="java.util.Date">
            <column name="ZHDLSJ" length="11" />
        </property>
        <property name="zhgmsj" type="java.util.Date">
            <column name="ZHGMSJ" length="11" />
        </property>
         <property name="qybj" type="java.lang.Integer">
            <column name="QYBJ" precision="22" scale="0"/>
        </property>
         <property name="glybj" type="java.lang.Integer">
            <column name="GLYBJ" precision="22" scale="0"/>
        </property>
      
    </class>
</hibernate-mapping>

Answer 2

主键生成方式改成<generator class="sequence">
<param name="sequence">你的sequence</param>
 </generator>

Answer 3

我的id是自己添加，所以没有sequence

Answer 4

看看你的数据库是否支持assigned这种主键生成策略

Answer 5

参考参考吧http://www.gold98.net/article.asp?id=183

Answer 6

sqlserver2008支持吗，这个从哪看，我在网上没找到相关说明……

Answer 7

看看hibernate的主键生成策略，里面有关于支持的数据库的主键生成   源码就有详解。