I am trying to implement a filter functionality in a Spring Boot App, but it fails when I try to filter based on an integer.

public class StudentSearchCriteria { private String firstName; private String lastName; private Integer yearOfStudy; }

public class StudentPage { private int pageNumber = 0; private int pageSize = 1; private Sort.Direction sortDirection = Sort.Direction.ASC; private String sortBy = "lastName"; }

public class StudentCriteriaRepository {

private final EntityManager entityManager;
private final CriteriaBuilder criteriaBuilder;

public StudentCriteriaRepository(EntityManager entityManager) {
    this.entityManager = entityManager;
    this.criteriaBuilder = entityManager.getCriteriaBuilder();
}

public Page<Student> findAllWithFilters(StudentPage studentPage,
                                        StudentSearchCriteria studentSearchCriteria) {
    CriteriaQuery<Student> criteriaQuery = criteriaBuilder.createQuery(Student.class);
    Root<Student> studentRoot = criteriaQuery.from(Student.class);
    Predicate predicate = getPredicate(studentSearchCriteria, studentRoot);
    criteriaQuery.where(predicate);

    setOrder(studentPage, criteriaQuery, studentRoot);

    TypedQuery<Student> typedQuery = entityManager.createQuery(criteriaQuery);
    typedQuery.setFirstResult(studentPage.getPageNumber() * studentPage.getPageSize());
    typedQuery.setMaxResults(studentPage.getPageSize());

    Pageable pageable = getPageable(studentPage);

    long studentsCount = getStudentsCount(predicate);
    return new PageImpl<>(typedQuery.getResultList(), pageable, studentsCount);
}




private Predicate getPredicate(StudentSearchCriteria studentSearchCriteria,
                               Root<Student> studentRoot) {
    List<Predicate> predicates = new ArrayList<>();
    if (Objects.nonNull(studentSearchCriteria.getFirstName())) {
        predicates.add(
                criteriaBuilder.like(studentRoot.get("firstName"),
                        "%"   studentSearchCriteria.getFirstName()   "%")
        );
    }

    if (Objects.nonNull(studentSearchCriteria.getLastName())) {
        predicates.add(
                criteriaBuilder.like(studentRoot.get("lastName"),
                        "%"   studentSearchCriteria.getLastName()   "%")
        );
    }

    if (Objects.nonNull(studentSearchCriteria.getYearOfStudy())) {
        predicates.add(
                criteriaBuilder.like(studentRoot.get("yearOfStudy"),
                        "%"   studentSearchCriteria.getYearOfStudy()   "%")
        );
    }
    return criteriaBuilder.and(predicates.toArray(new Predicate[0]));
}

CodePudding user response：

JPA can't execute like query between Integer and String. Try to convert Interger to String in yearOfStudy

if (Objects.nonNull(studentSearchCriteria.getYearOfStudy())) {
      predicates.add(
          criteriaBuilder.like(studentRoot.get("yearOfStudy").as(String.class), "%"   studentSearchCriteria.getYearOfStudy()   "%")
      );
}