从多对多用户角色关系中获取具有角色的用户的条件查询

Question

public class User {

    @ManyToMany
    @JoinTable(name = "t_user_roles",
                        joinColumns = @JoinColumn(name = "user_id"),
                        inverseJoinColumns = @JoinColumn(name = "role_id"))
    private Set<Role> roles = new HashSet<>();

}

public class Role {

    @Enumerated(EnumType.STRING)
    @Column(length = 20)
    private RoleType roleName;

}

public enum RoleType {

    ROLE_CUSTOMER("Customer"),
    ROLE_MANAGER("Manager"),
    ROLE_ADMIN("Administrator");

    private String name;

    private RoleType(String name) {
        this.name=name;
    }
    public String getName() {
        return name;
}

public PageImpl<UserDTO> getAllUserPage(String query,RoleType role,Pageable pageable) {
            CriteriaBuilder cb = entityManager.getCriteriaBuilder();
            CriteriaQuery<User> criteriaQuery = cb.createQuery(User.class);
            Root<User> root = criteriaQuery.from(User.class);

            List<Predicate> predicates = new ArrayList<>();
            Predicate finalPredicate = null;

            if (query != null && !query.isEmpty()) {
                String likeSearchText = "%" + query.toLowerCase(Locale.US) + "%";
                Predicate searchByUserFirstName = cb.like(cb.lower(root.get("firstName")), likeSearchText);
                Predicate searchByUserLastName = cb.like(cb.lower(root.get("lastName")), likeSearchText);
                Predicate searchByUserEmail = cb.like(cb.lower(root.get("email")), likeSearchText);
                predicates.add(cb.or(searchByUserFirstName,searchByUserLastName,searchByUserEmail));
            }
---------------------------------------------------------------------------------------------------
            if (role != null){
                Join<User, Role> joinRoles = root.join("roles");
                predicates.add(cb.equal(joinRoles.get("roleName"), role));
                System.err.println(role);
            }
---------------------------------------------------------------------------------------------------

            finalPredicate = cb.and(predicates.toArray(new Predicate[0]));

            criteriaQuery.orderBy(pageable.getSort().stream()
                    .map(order -> {
                        if (order.isAscending()) {
                            return cb.asc(root.get(order.getProperty()));
                        } else {
                            return cb.desc(root.get(order.getProperty()));
                        }
                    })
                    .collect(Collectors.toList()));

            criteriaQuery.where(finalPredicate);

            TypedQuery<User> typedQuery = entityManager.createQuery(criteriaQuery);
            typedQuery.setFirstResult((int)pageable.getOffset());
            typedQuery.setMaxResults(pageable.getPageSize());

            CriteriaQuery<Long> countQuery = cb.createQuery(Long.class);
            countQuery.select(cb.count(countQuery.from(User.class)));
            countQuery.where(finalPredicate);
            Long totalRecords = entityManager.createQuery(countQuery).getSingleResult();

            List<UserDTO> userDTOList = userMapper.map(typedQuery.getResultList());

            return new PageImpl<>(userDTOList, pageable, totalRecords);
    }

你好朋友，

正如您在上面看到的，我一直在尝试编写一个适用于所有可能场景的 Criteria API 查询。在此查询中，搜索部分完全动态地工作，并在所有可能的情况下提供结果。如果我不发送任何数据，它会带来所有用户。但是，我在添加用于根据角色执行搜索的代码块时遇到了问题。我在这里包含了所有代码，因为我认为其他查询可能存在问题。如您所见，我有 User 和 Role 类。我只裁剪了与角色相关的必要部分以使其简短。在多对多的关系中，我在网上搜索了如何根据用户的角色获取用户，但无济于事。角色在 Role 类中保存为 ENUM。该值没有问题，但是当我执行查询时，我得到错误

"org.hibernate.hql.internal.ast.QuerySyntaxException: Invalid path: 'generatedAlias1.roleName' [select count(generatedAlias0) from com.gpm.domains.User as generatedAlias0 where generatedAlias1.roleName=:param0]"

。尽管字段名称是正确的，但我无法以任何方式获得任何结果。你能帮帮我吗？