映射集<enum>使用@ElementCollection

本文介绍了映射集<enum>使用@ElementCollection的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有以下枚举:

package ir.raysis.tcs.rule.days; public enum Days { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY; }

我尝试将其映射为 Set 天，如下所示:

I tried to map it as a Set<Days> days as follows:

@ElementCollection(targetClass = Days.class) @JoinTable(name = "days",joinColumns = @JoinColumn(name = "rule_id")) @Column(name ="daysOfWeek", nullable = false) @Enumerated(EnumType.STRING) private Set<Days> days = new HashSet<>();

然而，它抛出了以下异常:

However, it throws the following exception:

Initial SessionFactory creation failed.hibernate.MappingException: Could not determine type for: java.util.Set, at table: rule, for columns: [org.hibernate.mapping.Column(days)] Apr 14, 2013 4:15:17 PM org.apache.catalina.core.StandardWrapperValve invoke SEVERE: Servlet.service() for servlet [jsp] in context with path [/ptcs] threw exception [javax.servlet.ServletException: java.lang.ExceptionInInitializerError] with root cause org.hibernate.MappingException: Could not determine type for: java.util.Set, at table: rule, for columns: [org.hibernate.mapping.Column(days)] at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:306) at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:290) at org.hibernate.mapping.Property.isValid(Property.java:217) at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:464) at org.hibernate.mapping.RootClass.validate(RootClass.java:235) at org.hibernate.cfg.Configuration.validate(Configuration.java:1362) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1865) at ir.raysis.tcs.db.HibernateUtil.<clinit>(HibernateUtil.java:18) at ir.raysis.tcs.db.SaveUpadteDelete.save(SaveUpadteDelete.java:33) at ir.raysis.tcs.db.dBAllFunc.save(dBAllFunc.java:35) at ir.raysis.tcs.db.AbsDBObject.save(AbsDBObject.java:45) at ir.raysis.tcs.action.CreateMemberAction.execute(CreateMemberAction.java:31) at org.apache.jsp.action.createMember_jsp._jspService(createMember_jsp.java:79) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579) at org.apache.tomcat.util.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1770) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source)

如何正确映射它?

推荐答案

为了未来的 googlers！最后我设法解决了这个问题，我只需要将注释放在我的代码中的其他地方，

for future googlers! finally i managed to solve the problem, i just had to put the annotations somewhere else in my code ,

@ElementCollection(targetClass = Days.class) @CollectionTable(name = "days", joinColumns = @JoinColumn(name = "rule_id")) @Column(name = "daysOfWeek", nullable = false) @Enumerated(EnumType.STRING) public Set<Days> getDays() { return days; }

如您所见，我在上面和 getter 方法之前编写了注释代码(而不是将其放在属性声明代码之前)并且问题已解决，任何能解释这是什么原因的人都将不胜感激.谢谢

as you can see i wrote the annotation code above and before the getter method(instead of placing it before the attribute declaration code) and problem solved, anyone who can explain me what causes this will be appreciated. thank you