请大家帮我看一下,运行Hibernate时报异常，该怎么处理？谢谢啦！
请大家帮我看一下，运行Hibernate时报异常，该怎么处理？这个异常是什么意思？谢谢啦！
如果我在网上搜这个异常是什么意思，是不是搜“org.hibernate.DuplicateMappingException: Duplicate collection role mapping wxw.hibernate.bean.person.emails
”这一行了？
我是模仿书上写的，麻烦说详细一点，谢谢啦！
异常：
%%%% Error Creating SessionFactory %%%%
org.hibernate.DuplicateMappingException: Duplicate collection role mapping wxw.hibernate.bean.person.emails
at org.hibernate.cfg.Configuration$MappingsImpl.addCollection(Configuration.java:2439)
at org.hibernate.cfg.annotations.CollectionBinder.bind(CollectionBinder.java:511)
at org.hibernate.cfg.AnnotationBinder.processElementAnnotations(AnnotationBinder.java:1906)
at org.hibernate.cfg.AnnotationBinder.processIdPropertiesIfNotAlready(AnnotationBinder.java:769)
at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:733)
at org.hibernate.cfg.AnnotationConfiguration.processArtifactsOfType(AnnotationConfiguration.java:636)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:359)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1377)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:954)
at wxw.hibernate.util.HibernateSessionFactory.rebuildSessionFactory(HibernateSessionFactory.java:76)
at wxw.hibernate.util.HibernateSessionFactory.getSession(HibernateSessionFactory.java:59)
at wxw.hibernate.test.t.main(t.java:69)
Exception in thread "main" java.lang.NullPointerException
at wxw.hibernate.test.t.main(t.java:71)
测试类：T
public class t {
public static void main(String[] args) {
person p =new person();
p.setName("用户1");
email e1 =new email();
e1.setAccount("user@126.com");
e1.setPassword("123456");
p.getEmails().add(e1);
email e2 = new email();
e2.setAccount("user@123.com");
e2.setPassword("123456");
p.getEmails().add(e2);
Session session = HibernateSessionFactory.getSession();
// session.beginTransaction();
Transaction trans = session.beginTransaction();
session.persist(p);
// session.getTransaction().commit();
trans.commit();
session.close();}
}
实体类：Email
@Entity
@Table(name = "tb_email")
public class email {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
public Integer id;
@Column(name = "account")
public String account;
@Column(name = "password")
public String password;
省略 get…,set…等方法
}
实体类：person
@Entity
@Table(name = "tb_person")
public class person {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
public Integer id;
@Column(name = "name")
public String name;
// fetch = FetchType.EAGER,
@OneToMany( targetEntity = email.class, cascade = {
CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.MERGE,
CascadeType.REFRESH })
@JoinColumns(value = { @JoinColumn(name = "person_id", referencedColumnName = "id") })
@OrderBy(value = "email desc")
public List<email> emails = new ArrayList<email>();
省略 get…,set…等方法
}
[解决办法]
