Query for multiple values of the same property with queryDSL and Spring Data JPA - spring-data-jpa

Question

Is there a way to query for multiple values of the same property with Spring DataREST JPA and querydsl? I am not sure what the format of the query URL should be and if I need extra customization in my bindings. I couldn't find anything in documentation. If I have a "student" table in my database with a "major" column with corresponding Student entity I would assume that querying for all students which have "math" and "science" majors would look like http://localhost:8080/students?major=math&major=science. However in this query only the first part is being taken and major=science is ignored

Answer 1

Below example customizes Querydsl web support to perform collection in operation. URI /students?major=sword&major=magic searches for students with major in ["sword", "magic"].
Entity and repository
public class Student {
private Long id;
private String name;
private String major;
}
public interface StudentRepos extends PagingAndSortingRepository<Student, Long>,
QuerydslPredicateExecutor<Student>,
QuerydslBinderCustomizer<QStudent> {
#Override
default void customize(QuerydslBindings bindings, QStudent root) {
bindings.bind(root.major)
.all((path, value) -> Optional.of(path.in(value)));
}
}
Test data
new Student("Arthur", "sword");
new Student("Merlin", "magic");
new Student("Lancelot", "lance");
Controller
#RestController
#RequestMapping("/students")
#RequiredArgsConstructor
public class StudentController {
private final StudentRepos studentRepos;
#GetMapping
ResponseEntity<List<Student>> getAll(Predicate predicate) {
Iterable<Student> students = studentRepos.findAll(predicate);
return ResponseEntity.ok(StreamSupport.stream(students.spliterator(), false)
.collect(Collectors.toList()));
}
}
Test case
#Test
#SneakyThrows
public void queryAll() {
mockMvc.perform(get("/students"))
.andExpect(status().isOk())
.andExpect(jsonPath("$").isArray())
.andExpect(jsonPath("$", hasSize(3)))
.andDo(print());
}
#Test
#SneakyThrows
void querySingleValue() {
mockMvc.perform(get("/students?major=sword"))
.andExpect(status().isOk())
.andExpect(jsonPath("$").isArray())
.andExpect(jsonPath("$", hasSize(1)))
.andExpect(jsonPath("$[0].name").value("Arthur"))
.andExpect(jsonPath("$[0].major").value("sword"))
.andDo(print());
}
#Test
#SneakyThrows
void queryMultiValue() {
mockMvc.perform(get("/students?major=sword&major=magic"))
.andExpect(status().isOk())
.andExpect(jsonPath("$").isArray())
.andExpect(jsonPath("$", hasSize(2)))
.andExpect(jsonPath("$[0].name").value("Arthur"))
.andExpect(jsonPath("$[0].major").value("sword"))
.andExpect(jsonPath("$[1].name").value("Merlin"))
.andExpect(jsonPath("$[1].major").value("magic"))
.andDo(print());
}
The full Spring Boot application is in Github