Criteria.DISTINCT_ROOT_ENTITY不会阻止重复的对象 [英] Criteria.DISTINCT_ROOT_ENTITY doesn't prevent duplicated objects

问题描述

我有以下dao方法：

  @Override 
 public List< AdminRole> findAll（）{
 Session session = sessionFactory.getCurrentSession（）; 
 Criteria criteria = session.createCriteria（AdminRole.class）; 
 criteria.setResultTransformer（Criteria.DISTINCT_ROOT_ENTITY）; 
 return criteria.list（）; 
} 
  

其实我想从数据库中检索所有条目。

有时我会看到重复的内容。当我使用AdminRole添加用户时，会发生这种情况。

我读过使用 EAGER 获取类型这应该是修复添加以下行：

  criteria.setResultTransformer（Criteria.DISTINCT_ROOT_ENTITY）; 
  

但这并不能帮助我。

<
$ b

  @Entity 
 @Table（name =terminal_admin_role）
 public class AdminRole {
 
 @Id 
 @Column（name =role_id，nullable = false，unique = true）
 @GeneratedValue（strategy = GenerationType.SEQUENCE，generator =user_id ）
 @SequenceGenerator（name =user_id，sequenceName =user_id）
 private长adminId; 
 
 @Column（name =role）
私人字符串角色; 
 
 public AdminRole（String role）{
 this.role = role; 
} 
 
 public AdminRole（）{
} 
 
 //获得集合
 
 @Override 
 public String toString（）{
返回角色; 
 
 $ b @Override 
 public boolean equals（Object o）{
 if（this == o）{
 return true; 
} 
 if（！（o instanceof AdminRole））{
 return false; 
} 
 
 AdminRole adminRole =（AdminRole）o; 
 
 if（！role.equals（adminRole.role））{
 return false; 
} 
 
返回true; 
 
 
 @Override 
 public int hashCode（）{
 return role.hashCode（）; 
 
 
 code 
 
 
 
 
 
  @Entity 
 @Table（name =terminal_admin）
 public class TerminalAdmin {
 @ManyToMany（fetch = FetchType.EAGER， cascade = CascadeType.ALL）
 @JoinTable（name =admin_role，joinColumns = {
 @JoinColumn（name =admin_id，nullable = false）}，
 inverseJoinColumns = {@JoinColumn （name =role_id，
 nullable = false）}）
 private Set< AdminRole> adminRoles; 
 // ... 
} 
  
 
 
 
 PS 
 
 
 
我无法切换抓取类型。
 
 
 
我不想把这个列表放到集合中。
解决方案
没有理由使用 DISTINCT_ROOT_ENTITY 或类似的东西，只需要：
  session.createCriteria（AdminRole.class）.list（）; 
  
如果您得到重复项，那么您确实在数据库中有它们。检查直接或通过级联从其他实体保存 AdminRole  s的代码。
 
 
 
当级联 PERSIST  /  MERGE 来自其他实体的操作，请确保该操作级联到持久/分离的 AdminRole 实例，而不是瞬态（新）。
 
I have following dao method:
@Override
public List<AdminRole> findAll() {
    Session session = sessionFactory.getCurrentSession();
    Criteria criteria = session.createCriteria(AdminRole.class);
    criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
    return criteria.list();
}
Actually I want to retrieve all entries from database.

Sometimes I see duplicates. This happens when I add user with AdminRole.

I have read that it is possible when I use EAGER fetch type and this should be fix adding following line:
criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
But this doesn't help me.

my mapping:
@Entity
@Table(name = "terminal_admin_role")
public class AdminRole {

    @Id
    @Column(name = "role_id", nullable = false, unique = true)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "user_id")
    @SequenceGenerator(name = "user_id", sequenceName = "user_id")
    private Long adminId;

    @Column(name = "role")
    private String role;

    public AdminRole(String role) {
        this.role = role;
    }

    public AdminRole() {
    }

    // get set

    @Override
    public String toString(){
        return role;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (!(o instanceof AdminRole)) {
            return false;
        }

        AdminRole adminRole = (AdminRole) o;

        if (!role.equals(adminRole.role)) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        return role.hashCode();
    }
}
and
@Entity
@Table(name = "terminal_admin")
public class TerminalAdmin {
    @ManyToMany(fetch=FetchType.EAGER,cascade=CascadeType.ALL)
    @JoinTable(name = "admin_role", joinColumns = { 
        @JoinColumn(name = "admin_id", nullable = false) }, 
        inverseJoinColumns = { @JoinColumn(name = "role_id", 
                nullable = false) })
    private Set<AdminRole> adminRoles;      
    //...
}


P.S.

I cannot switch fetch type.

I don't want to put this list into set.
解决方案
There is no reason to use DISTINCT_ROOT_ENTITY or anything similar, all you need is:
session.createCriteria(AdminRole.class).list();
If you get duplicates, then you really have them in the database. Check the code which saves AdminRoles either directly or by cascading from other entities.

When cascading PERSIST/MERGE operations from other entities, make sure that the operation is cascaded to a persistent/detached AdminRole instance, not to a transient (new) one.

                        
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