用QuerydslJpaPredicateExecutor替换不推荐使用的QuerydslJpaRepository失败

用QuerydslJpaPredicateExecutor替换不推荐使用的QuerydslJpaRepository失败

使用 Spring Boot 2.1.1，以下解决方案可能会对您有所帮助。关键是扩展

JpaRepositoryFactory

和覆盖该方法

getRepositoryFragments(Repositorymetadatametadata)

。在这种方法中，您可以为任何自定义存储库提供基本（或更具体的片段）实现，每个扩展存储库都应采用这些实现。

让我给你看一个例子：

QueryableReadRepository：

@NoRepositoryBeanpublic interface QueryableReadRepository<T> extends Repository<T, String> {  List<T> findAll(Predicate predicate);  List<T> findAll(Sort sort);  List<T> findAll(Predicate predicate, Sort sort);  List<T> findAll(OrderSpecifier<?>... orders);  List<T> findAll(Predicate predicate, OrderSpecifier<?>... orders);  Page<T> findAll(Pageable page);  Page<T> findAll(Predicate predicate, Pageable page);  Optional<T> findOne(Predicate predicate);  boolean exists(Predicate predicate);}

以下界面结合了不同的存储库。

资料储存库：

@NoRepositoryBeanpublic interface DataRepository<T>    extends CrudRepository<T, String>, QueryableReadRepository<T> {}

现在，您特定的域存储库可以从DataRepository扩展：

@Repositorypublic interface UserRepository extends DataRepository<UserEntity> {}

QueryableReadRepositoryImpl：

@Transactionalpublic class QueryableReadRepositoryImpl<T> extends QuerydslJpaPredicateExecutor<T>    implements QueryableReadRepository<T> {  private static final EntityPathResolver resolver = SimpleEntityPathResolver.INSTANCE;  private final EntityPath<T> path;  private final PathBuilder<T> builder;  private final Querydsl querydsl;  public QueryableReadRepositoryImpl(JpaEntityInformation<T, ?> entityInformation,      EntityManager entityManager) {    super(entityInformation, entityManager, resolver, null);    this.path = resolver.createPath(entityInformation.getJavaType());    this.builder = new PathBuilder<T>(path.getType(), path.getmetadata());    this.querydsl = new Querydsl(entityManager, builder);  }  @Override  public Optional<T> findOne(Predicate predicate) {    return super.findOne(predicate);  }  @Override  public List<T> findAll(OrderSpecifier<?>... orders) {    return super.findAll(orders);  }  @Override  public List<T> findAll(Predicate predicate, Sort sort) {    return executeSorted(createQuery(predicate).select(path), sort);  }  @Override  public Page<T> findAll(Predicate predicate, Pageable pageable) {    return super.findAll(predicate, pageable);  }  @Override  public List<T> findAll(Predicate predicate) {    return super.findAll(predicate);  }  public List<T> findAll(Sort sort) {    return executeSorted(createQuery().select(path), sort);  }  @Override  public Page<T> findAll(Pageable pageable) {    final JPQLQuery<?> countQuery = createCountQuery();    JPQLQuery<T> query = querydsl.applyPagination(pageable, createQuery().select(path));    return PageableExecutionUtils.getPage(        query.distinct().fetch(),         pageable,        countQuery::fetchCount);  }  private List<T> executeSorted(JPQLQuery<T> query, Sort sort) {    return querydsl.applySorting(sort, query).distinct().fetch();  }}

CustomRepositoryFactoryBean ：

public class CustomRepositoryFactoryBean<T extends Repository<S, I>, S, I>    extends JpaRepositoryFactoryBean<T, S, I> {  public CustomRepositoryFactoryBean(Class<? extends T> repositoryInterface) {    super(repositoryInterface);  }  protected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager) {    return new CustomRepositoryFactory(entityManager);  }

CustomRepositoryFactory ：

public class CustomRepositoryFactory extends JpaRepositoryFactory {  private final EntityManager entityManager;  public CustomRepositoryFactory(EntityManager entityManager) {    super(entityManager);    this.entityManager = entityManager;  }  @Override  protected RepositoryFragments getRepositoryFragments(Repositorymetadata metadata) {    RepositoryFragments fragments = super.getRepositoryFragments(metadata);    if (QueryableReadRepository.class.isAssignableFrom(        metadata.getRepositoryInterface())) {      JpaEntityInformation<?, Serializable> entityInformation =getEntityInformation(metadata.getDomainType());      Object queryableFragment = getTargetRepositoryViaReflection(          QueryableReadRepositoryImpl.class, entityInformation, entityManager);      fragments = fragments.append(RepositoryFragment.implemented(queryableFragment));    }    return fragments;  }

主班：

@EnableJpaRepositories(repositoryFactoryBeanClass = CustomRepositoryFactoryBean.class)public class App {}

这样做的好处是，您只能为自定义存储库提供一个（片段）实现。基本存储库实现仍然是Spring的默认实现。该示例提供了新的存储库，但您也可以覆盖

QuerydslPredicateExecutor

in的默认实现

CustomRepositoryFactory