映射集<枚举>使用@ElementCollection

本文介绍了映射集<枚举>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< Days ; 天如下：

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<>();

但是，它会引发以下异常：

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？

推荐答案

为未来的Google员工！ 最后我设法解决了这个问题，我只是把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; }

如你所见，我写了上面和之前的注释代码而不是将它放在属性声明代码之前）并且问题解决了，任何可以解释我什么原因的人将不胜感激。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