How to join multiple queryDSL tables - spring

Question

I have some tables and I want to get result using queryDSL join, but haven't found any examples on multiple joins using queryDSL.
I have these tables:
Account table: accountId (PK) | email | password
account_profile table: accountId (PK)(fk to account) | nickname
Community table: articleId (PK) | accountId (fk to account) | title | content
Now I want below JPQL to be queryDSL code
select r from community r join r.account.profile a where a.nickname = :nickname
I have entity metamodels - QAccount, QAccountProfile, QCommunity
Additionally, I have to get the result with pagination, so the query should be called with pageable object.
Here is my work that doesn't work yet.
JPAQuery</*What generic type expected?*/> query = new JPAQuery</*???*/>(entityManager);
Predicate predicate = query.from(QCommunity.community).join(/*join directly accountProfile? or account? is it QEntity or real entity?*/);
// where should I place nickname matching condition ?
...
list = (repository.findAll(predicate, pageable)).getContent();
Where should I place the nickname matching condition?
EDIT: Appended entity information
Account.java
#Entity
#Table(name="account", uniqueConstraints={
#UniqueConstraint(columnNames="account_seq"),
#UniqueConstraint(columnNames="email")
})
#DynamicInsert
#DynamicUpdate
#Data
#EqualsAndHashCode
#ToString(includeFieldNames=true)
#RequiredArgsConstructor(staticName="of")
#NoArgsConstructor
public class Account implements Serializable{
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="account_seq", nullable=false, unique=true)
private Integer accountId;
#Column(name="email", nullable=false, unique=true)
#NonNull
private String email;
#NonNull
private String password;
#OneToOne(cascade=CascadeType.ALL, mappedBy="account")
private AccountProfile profile;
#OneToOne(cascade=CascadeType.ALL, mappedBy="account")
private AccountSecurity security;
}
AccountProfile.java
#Entity
#Table(name="account_profile", uniqueConstraints={
#UniqueConstraint(columnNames={"account_seq"}),
#UniqueConstraint(columnNames={"nickname"})
})
#DynamicInsert
#DynamicUpdate
#Data
#EqualsAndHashCode
#ToString(includeFieldNames=true)
#RequiredArgsConstructor(staticName="of")
#NoArgsConstructor
public class AccountProfile implements Serializable{
private static final long serialVersionUID = 1L;
#Id
#OneToOne(cascade=CascadeType.ALL)
#JoinColumn(name="account_seq", referencedColumnName="account_seq")
private Account account;
#Column(name="nickname", nullable=false)
#NonNull
private String nickname;
}
Community.java
#Entity
#Table(name="community", uniqueConstraints = {
#UniqueConstraint(columnNames="article_seq")
})
#DynamicInsert
#DynamicUpdate
#Data
#NoArgsConstructor
#EqualsAndHashCode
#ToString(includeFieldNames=true)
public class Community {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="article_seq", nullable=false, unique=true)
private Long articleId;
#ManyToOne(cascade=CascadeType.ALL)
#JoinColumn(name="account_seq", referencedColumnName="account_seq")
private Account account;
#Column(name="title", nullable=false)
private String title;
#Column(name="content", nullable=false)
private String content;
#Temporal(TemporalType.TIMESTAMP)
#Column(name="reg_dt")
private Date date;
#Column(name="read_cnt", nullable=false)
private int readCount;
#Column(name="attach_url")
private String attachUrl;
#Column(name="attach_filename")
private String attachFileName;
#OneToMany(cascade=CascadeType.ALL, mappedBy="article")
private Set<CommunityReply> replies;
}
EDIT: PROBLEM SOLVED
To help others who is facing the problem like me, I am gonna post my working code. the code is searching any community articles with matching specific nickname.
#PersistenceContext
private EntityManager entityManager;
private List<Community> getList(int pageNo, String keyword, int rowsOnPage){
int offset = (pageNo -1) * rowsOnPage;
int limit = rowsOnPage;
JPAQuery<Community> query = new JPAQuery<Community>(entityManager);
QCommunity qCommunity = QCommunity.community;
QAccount qAccount = QAccount.account;
QAccountProfile qAccountProfile = QAccountProfile.accountProfile;
return query
.from(qCommunity)
.innerJoin(qCommunity.account ,qAccount)
.innerJoin(qAccount.profile, qAccountProfile)
.where(qAccountProfile.nickname.like("%"+keyword+"%"))
.orderBy(qCommunity.articleId.desc())
.offset(offset)
.limit(limit)
.fetch();
}

Answer 1

First of all, declare a custom extended base repository class for QueryDSL queries.
First the interface:
#NoRepositoryBean
public interface ExtendedQueryDslJpaRepository<T, ID extends Serializable>
extends JpaRepository<T, ID>, QueryDslPredicateExecutor<T> {
<T1> Page<T1> findAll(JPQLQuery jpqlQuery, Pageable pageable);
}
And then the implementation:
public class ExtendedQueryDslJpaRepositoryImpl<T, ID extends Serializable>
extends QueryDslJpaRepository<T, ID> implements ExtendedQueryDslJpaRepository<T, ID> {
private static final EntityPathResolver DEFAULT_ENTITY_PATH_RESOLVER = SimpleEntityPathResolver.INSTANCE;
private final EntityPath<T> path;
private final PathBuilder<T> builder;
private final Querydsl querydsl;
private EntityManager entityManager;
public ExtendedQueryDslJpaRepositoryImpl(JpaEntityInformation<T, ID> entityInformation, EntityManager entityManager) {
this(entityInformation, entityManager, DEFAULT_ENTITY_PATH_RESOLVER);
}
public ExtendedQueryDslJpaRepositoryImpl(JpaEntityInformation<T, ID> entityInformation,
EntityManager entityManager, EntityPathResolver resolver) {
super(entityInformation, entityManager);
this.path = resolver.createPath(entityInformation.getJavaType());
this.builder = new PathBuilder(this.path.getType(), this.path.getMetadata());
this.querydsl = new Querydsl(entityManager, this.builder);
this.entityManager = entityManager;
}
#Override
public <T1> Page<T1> findAll(JPQLQuery jpqlQuery, Pageable pageable) {
// Count query
final JPQLQuery<?> countQuery = jpqlQuery;
// Apply pagination
JPQLQuery<T1> query = querydsl.applyPagination(pageable, jpqlQuery);
// Run query
return PageableExecutionUtils.getPage(query.fetch(), pageable, countQuery::fetchCount);
}
}
Define the new class as base for base and repositories in a #Configuration class.
#Configuration
#EnableJpaRepositories(basePackageClasses = ..., repositoryBaseClass = ExtendedQueryDslJpaRepositoryImpl.class)
Your repositories then should extend from the new interface (which of course extends JpaRepository):
#Repository
public interface CommunityRepository extends ExtendedQueryDslJpaRepository<Community, Long> {
}
Then, you can try the following code:
String nickname = "nick";
QAccount account = QAccount.account;
QAccountProfile accountProfile = QAccountProfile.accountProfile;
QCommunity community = QCommunity.community;
JPQLQuery query = new JPAQuery(entityManager);
BooleanBuilder predicate = new BooleanBuilder();
predicate.and(accountProfile.nickname.eq(nickname));
// select r from community r join r.account.profile a where a.nickname = :nickname
query.from(community)
.join(community.account, account)
.join(account.accountProfile, accountProfile)
.where(predicate);
repository.findAll(query, pageable);
Hope that helps.

Answer 2

I found one solution as
QEntity qEntity1 = new QEntity("qEntity1");
QEntity qEntity2 = new QEntity("qEntity2");
so while querying you can use
new JPAQueryFactory(entityManager).from(qSampleBO)
.innerJoin(qEntity1).on(qEntity1.id.eq(qSampleBO.address.id))
.innerJoin(qEntity2).on(qEntity2.id.eq(qSampleBO.secondary_address.id))
...