报错了 这是为什么？

Question

org.springframework.orm.hibernate3.HibernateSystemException: ids for this class must be manually assigned before calling save(): com.wsc.po.User; nested exception is org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save(): com.wsc.po.User
at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:676)
at org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:412)
at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:424)
at org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374)
at org.springframework.orm.hibernate3.HibernateTemplate.save(HibernateTemplate.java:694)
at com.wsc.DAO.impl.UserDAOImpl.createUser(UserDAOImpl.java:22)
at com.wsc.service.impl.Regeditimpl.saveUser(Regeditimpl.java:16)
at com.wsc.action.RegeditController.onSubmit(RegeditController.java:34)
at org.springframework.web.servlet.mvc.SimpleFormController.processFormSubmission(SimpleFormController.java:267)
at org.springframework.web.servlet.mvc.AbstractFormController.handleRequestInternal(AbstractFormController.java:265)
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:511)
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(Thread.java:619)

Answer 1

hibernate出现这个错误的原因有可能因为，你的表中有个主键。 但是在执行save()的时候却没有给Id设置值，如调用xxx.setId(..)等方法，才会出现。  你看下你主键的生成策略是怎样的。

Answer 2

在hibernate映射文件XX.hbm.xml对应实体ID值设置成UUID主键自动生成策略就可以了！<id name="userid" type="string">
           <column name="USERID" length="32" />
           <generator class="uuid"></generator>
</id>