Add Querydsl support
Tip submitted by @omrzljak, updated by @arnaud-deprez
In some cases Spring Data query possibilities are not enough to make your queries. You can use @Query
annotation and write your own. Some of us like to write type safe queries like Querydsl provides.
Generated Predicate classes
An important part of Querydsl are generated domain classes for queries so called Predicate. In case of spring-data-mongodb these are generated by the Java annotation post processing tool.
Gradle plugin
There is also Gradle plugin for Querydsl which supports configuration for spring-data-mongodb.
Maven plugin
There is also a plugin for Maven. Maven configuration is fully described in the chapter Maven integration of the documentation. You also need to perform the steps below.
Note: Do not include the org.slf4j
dependency because it is included in Spring Boot.
Changes
build.gradle
In build.gradle
, add the dependency to Querydsl plugin
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "gradle.plugin.com.ewerk.gradle.plugins:querydsl-plugin:1.0.9"
}
}
apply from: 'gradle/querydsl.gradle'
Define the Querydsl version
to use in your gradle.properties
querydsl_version=4.1.4
Then create a the file gradle/querydsl.gradle
with
apply plugin: "com.ewerk.gradle.plugins.querydsl"
sourceSets {
main {
java {
srcDir "$buildDir/generated/source/apt/main"
}
}
}
querydsl {
// we use mongodb
springDataMongo = true
querydslSourcesDir = "$buildDir/generated/source/apt/main"
}
dependencies {
compile "com.querydsl:querydsl-mongodb:${querydsl_version}"
compileOnly "com.querydsl:querydsl-apt:${querydsl_version}"
}
Note we use MongoDB but Querydsl plugin supports also more options.
If you run gradle build
you will see output like this
Note: Generating net.jogat.names.domain.QName for [net.jogat.names.domain.Name]
For every domain class which is annotated with @Document Querydsl plugin will generate one Predicate class.
Change Repository classes
If you have a domain class for example Name
, then you have also a NameRepository
class. You have to change every Repository class to extend from QueryDslPredicateExecutor
.
public interface NameRepository extends MongoRepository<Name, String>, QueryDslPredicateExecutor<Name> {
This will extend your repository class with extra methods supporting Querydsl (see )
Web support
To extend the rest controller for support parameterized request, you have to add com.mysema.query.types.Predicate
annotated with org.springframework.data.querydsl.binding.QuerydslPredicate
to the method parameters:
@RestController
@RequestMapping("/api")
class NameResource {
private final NameRepository nameRepository;
public NameResource(NameRepository nameRepository) {
this.nameRepository = nameRepository;
}
@RequestMapping(value = "/names",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
@Timed
public ResponseEntity<List<Name>> getAllNames(@QuerydslPredicate(root = Name.class) Predicate predicate,
Pageable pageable) {
log.debug("REST request to get a page of Name");
Page<Name> page = nameRepository.findAll(predicate, pageable);
HttpHeaders headers = PaginationUtil.generatePaginationHttpHeaders(page, "/api/names");
return new ResponseEntity<>(page.getContent(), headers, HttpStatus.OK);
}
...
}
Also in NameResourceIntTest
you have to support QuerydslPredicateArgumentResolver
:
public class NameResourceIntTest {
...
@Autowired
private NameRepository nameRepository;
@Autowired
private QuerydslPredicateArgumentResolver querydslPredicateArgumentResolver;
@PostConstruct
public void setup() {
MockitoAnnotations.initMocks(this);
NameResource nameResource = new nameResource(nameRepository);
this.restNameMockMvc = MockMvcBuilders.standaloneSetup(nameResource)
.setCustomArgumentResolvers(pageableArgumentResolver, querydslPredicateArgumentResolver)
.setMessageConverters(jacksonMessageConverter).build();
}
...
}
More details can be found in the documentation.
Write type safe queries
Gradle or maven plugins have generated class QName which can be used for writing queries for Name.class. Here is Java example:
QName name = QName.name;
// count all names whose list "categorie" contains string "TOP_EVER"
nameRepository.count(name.categories.contains("TOP_EVER"));