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Using Hibernate criteria to retrieve data from multiple tables without setting up entity display

I have a problem in my project. I am trying to create a search function to search for users from a user table, but at the same time I also want to get the corresponding " url " of a user avatar from another Avatar table. I want to create a hard match between these two tables. How can I do this flexibly using Hibernate criteria? Both tables use the primary key " loginID ".

I have two classes:

public class User{
    private String loginID;
    private String screenname;
    ......
}
public class Avatar{
    private Integer id;
    private String loginID;
    private String url;
    .......
}

What I wrote:

  public List<Users> searchLogin(String keywords, int startFrom) {
        List<Users> userList = new ArrayList<Users>();
        try {
            Session session = HibernateUtil.beginTransaction();
            Criteria criteria = session.createCriteria(Users.class,"users");
            criteria.add(Restrictions.ilike("loginID", keywords, MatchMode.ANYWHERE));
            userList = criteria.list();
            if (session.isOpen()) {
                session.close();
            }
            return userList;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

Thanks guys!

+5
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3 answers

Use HQL

from User u,Avatar a where where u.loginID = a.loginID and u.loginID = :loginID

This will return a list of arrays [User, Avatar].

+3

, , google . HQL.

:

    CriteriaBuilder builder = em.getCriteriaBuilder();
    CriteriaQuery<Tuple> criteria = builder.createTupleQuery();
    Root<EntityA> entityARoot= criteria.from(EntityA.class);
    Root<EntityB> entityBRoot = criteria.from(EntityB.class);

    //Predicates
    List<Predicate> predicates = new ArrayList<>();
    //Add the predicates you need

    //And predicates
    List<Predicate> andPredicates = new ArrayList<>();
    andPredicates.add(builder.equal(entityARoot.get("id"), entityBRoot.get("id")));
    andPredicates.add(builder.and(predicates.toArray(new Predicate[0])));

    criteria.multiselect(entityARoot, entityBRoot);
    criteria.where(andPredicates.toArray(new Predicate[0]));

    TypedQuery<Tuple> query = em.createQuery(criteria);

    List<Tuple> result = query.getResultList();
+6

"loginID".

? Avatar, 'id', id/primary key?

, Avatar User loginId. - . :

@Entity
public class User
{
    @Id
    private String loginId;
    private String screenName;
    @OneToOne(mappedBy = "user")
    private Avatar avatar;
}

@Entity
public class Avatar
{
    @Id
    private Integer id;
    @OneToOne
    private User user;
    private String url;
}

User URL- Avatar, User, User Avatar, , URL Avatar , , Object User Avatar .

User user = fetchUserJoinAvatar("123");
String url = user.getAvatar().getUrl();

public User fetchUserJoinAvatar(String loginId)
{
    CriteriaBuilder cb = em.getCriteriaBuilder();
    CriteriaQuery<User> query = cb.createQuery(User.class);

    Root<User> user = query.from(User.class);
    user.fetch("avatar");
    query.select(user).where(cb.equal(user.get("loginId"), loginId));
    return em.createQuery(query).getSingleResult();
}
+2

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