相关疑难解决方法(0)

EntityManager.merge() 可以插入新对象并更新现有对象.

为什么要使用persist()(只能创建新对象)？

我有2个实体:Account和AccountRole.

public class Account {
   private AccountRole accountRole;

   @ManyToOne(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
   public AccountRole getAccountRole() {
      return accountRole;
   }

.

public class AccountRole {
    private Collection<Account> accounts = new ArrayList<Account>();

    @OneToMany(mappedBy = "accountRole", fetch = FetchType.EAGER)
    public Collection<Account> getAccounts() {
         return accounts;
    }

当我从数据库中获取accountRole并试图坚持我的问​​题时出现问题Account.此时我刚创建了我的帐户,角色已经存在于db中.

AccountRole role = accountService.getRoleFromDatabase(AccountRoles.ROLE_USER);
account.setAccountRole(role);

//setting both ways, as suggested
public void setAccountRole(AccountRole accountRole) {
    accountRole.addAccount(this);
    this.accountRole = accountRole;
}

entityManager.persist(account); // finally in my DAO

我读到这个: …

我正在尝试使用Hibernate EntityManager persist方法将一个人pojo插入mysql数据库,

entityManagerTransactionService.getEntityManager().persist(TemplateObject);

得到这个例外,

 javax.persistence.PersistenceException:
 org.hibernate.PersistentObjectException: detached entity passed to
 persist: com.esupu.base.model.pojo.common.TitleType    at
 org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1387)....

还有更多......

 Caused by: org.hibernate.PersistentObjectException: detached entity
 passed to persist: com.esupu.base.model.pojo.common.TitleType  at
 org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:141)
    at
 org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:843)

我的Person.java类是,

@Entity
public class Person extends TemplateObject {

    @OneToOne(cascade = { CascadeType.MERGE, CascadeType.PERSIST,CascadeType.REFRESH })
        private TitleType titleType;
        private String middle;
        private String last;
        @OneToOne(cascade = { CascadeType.ALL })
        private Address address;
        private Date birthdate;
        private String email;
        private String telephone;
        private String fax;
        @OneToOne(cascade = { CascadeType.ALL })
        private Location location; …