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jpa中::::_项目学生：JPA标准查询

發(fā)布時(shí)間：2023/12/3 编程问答 35 豆豆

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jpa中::::

這是Project Student的一部分。其他職位包括帶有Jersey的Webservice Client，帶有Jersey的 Webservice Server ，業(yè)務(wù)層，具有Spring Data的持久性，分片集成測(cè)試數(shù)據(jù)和Webservice Integration 。

我們已經(jīng)介紹了CRUD的基本操作，但是并沒(méi)有花太多時(shí)間。 Spring Data使包含基本搜索變得容易，但是擁有其他標(biāo)準(zhǔn)選項(xiàng)也很重要。 JPA標(biāo)準(zhǔn)查詢是最重要的查詢之一。

Spring Data JPA教程– JPA Criteria Queries [http://www.petrikainulainen.net]是對(duì)該材料的很好介紹。

設(shè)計(jì)決策

JPA標(biāo)準(zhǔn) –我使用的是JPA標(biāo)準(zhǔn)搜索，而不是querydsl。稍后我將返回querydsl。

局限性

違反封裝 –此設(shè)計(jì)需要打破使每個(gè)層完全不了解其他層的實(shí)現(xiàn)細(xì)節(jié)的體系結(jié)構(gòu)目標(biāo)。這是一個(gè)非常小的違反行為-僅JPA規(guī)范-我們?nèi)匀槐仨毺幚矸猪?yè)。將它們放在一起，我覺(jué)得此時(shí)過(guò)分擔(dān)心這個(gè)還為時(shí)過(guò)早。

Web服務(wù) -不更新web服務(wù)客戶端和服務(wù)器。同樣，我們?nèi)匀槐仨毺幚矸猪?yè)，并且無(wú)論如何我們現(xiàn)在要做的任何事情都必須更改。

重構(gòu)先前的工作

我對(duì)以前的工作有三點(diǎn)改變。

findCoursesByTestRun（）

我已經(jīng)定義了方法：

List findCoursesByTestRun(TestRun testRun);

在課程庫(kù)中。那沒(méi)有預(yù)期的效果。我需要的是

List findCoursesByTestRun_Uuid(String uuid);

對(duì)調(diào)用代碼進(jìn)行適當(dāng)?shù)母摹?或者，您可以只使用下面討論的JPA條件查詢。

FinderService和ManagerService

這來(lái)自Jumpstart網(wǎng)站上的研究。作者將標(biāo)準(zhǔn)服務(wù)接口分為兩部分：

FinderService –只讀操作（搜索）
ManagerService –讀寫(xiě)操作（創(chuàng)建，更新，刪除）

這很有道理，例如，當(dāng)我們可以在類(lèi)與方法級(jí)別上進(jìn)行操作時(shí)，通過(guò)AOP添加行為會(huì)容易得多。我在現(xiàn)有代碼中做了適當(dāng)?shù)母摹?

查找錯(cuò)誤

我已經(jīng)修復(fù)了FindBugs發(fā)現(xiàn)的許多問(wèn)題。

元數(shù)據(jù)

我們首先允許對(duì)持久對(duì)象的元數(shù)據(jù)訪問(wèn)。這使我們能夠創(chuàng)建可以通過(guò)JPA實(shí)現(xiàn)進(jìn)行優(yōu)化的查詢。

import javax.persistence.metamodel.SingularAttribute; import javax.persistence.metamodel.StaticMetamodel;@StaticMetamodel(Course.class) public class Course_ {public static volatile SingularAttribute<Course, TestRun> testRun; }

和

@StaticMetamodel(TestRun.class) public class TestRun_ {public static volatile SingularAttribute<TestRun, String> uuid; }

由于約定優(yōu)于配置，因此需要類(lèi)的名稱。

有關(guān)此功能的討論，請(qǐng)參見(jiàn)靜態(tài)元數(shù)據(jù) [jboss.org]。

技術(shù)指標(biāo)

現(xiàn)在，我們可以使用現(xiàn)在可用的元數(shù)據(jù)創(chuàng)建查詢規(guī)范。這是一個(gè)稍微復(fù)雜的查詢，因?yàn)槲覀冃枰钊胙芯拷Y(jié)構(gòu)。（這不需要實(shí)際的聯(lián)接，因?yàn)閠estrun uuid用作外鍵。）

public class CourseSpecifications {/*** Creates a specification used to find courses with the specified testUuid.* * @param testRun* @return*/public static Specification<Course> testRunIs(final TestRun testRun) {return new Specification<Course>() {@Overridepublic Predicate toPredicate(Root<Course> courseRoot, CriteriaQuery<?> query, CriteriaBuilder cb) {Predicate p = null;if (testRun == null || testRun.getUuid() == null) {p = cb.isNull(courseRoot.<Course_> get("testRun"));} else {p = cb.equal(courseRoot.<Course_> get("testRun").<TestRun_> get("uuid"), testRun.getUuid());}return p;}};} }

一些文檔建議我可以使用get（Course_.testRun）代替get（“ testRun”），但是eclipse在get（）方法上將其標(biāo)記為類(lèi)型沖突。你的旅費(fèi)可能會(huì)改變。

Spring數(shù)據(jù)倉(cāng)庫(kù)

我們必須告訴Spring Data我們正在使用JPA Criteria查詢。這是通過(guò)擴(kuò)展JpaSpecificationExecutor接口來(lái)完成的。

@Repository public interface CourseRepository extends JpaRepository<Course, Integer>,JpaSpecificationExecutor<Course> {Course findCourseByUuid(String uuid);List findCoursesByTestRunUuid(String uuid); }

FinderService實(shí)施

現(xiàn)在，我們可以在我們的服務(wù)實(shí)現(xiàn)中使用JPA規(guī)范。如上所述，使用JPA Criteria Specification違反了封裝。

import static com.invariantproperties.sandbox.student.specification.CourseSpecifications.testRunIs;@Service public class CourseFinderServiceImpl implements CourseFinderService {@Resourceprivate CourseRepository courseRepository;/*** @see com.invariantproperties.sandbox.student.business.FinderService#* count()*/@Transactional(readOnly = true)@Overridepublic long count() {return countByTestRun(null);}/*** @see com.invariantproperties.sandbox.student.business.FinderService#* countByTestRun(com.invariantproperties.sandbox.student.domain.TestRun)*/@Transactional(readOnly = true)@Overridepublic long countByTestRun(TestRun testRun) {long count = 0;try {count = courseRepository.count(testRunIs(testRun));} catch (DataAccessException e) {if (!(e instanceof UnitTestException)) {log.info("internal error retrieving classroom count by " + testRun, e);}throw new PersistenceException("unable to count classrooms by " + testRun, e, 0);}return count;}/*** @see com.invariantproperties.sandbox.student.business.CourseFinderService#* findAllCourses()*/@Transactional(readOnly = true)@Overridepublic List<Course> findAllCourses() {return findCoursesByTestRun(null);}/*** @see com.invariantproperties.sandbox.student.business.CourseFinderService#* findCoursesByTestRun(java.lang.String)*/@Transactional(readOnly = true)@Overridepublic List<Course> findCoursesByTestRun(TestRun testRun) {List<Course> courses = null;try {courses = courseRepository.findAll(testRunIs(testRun));} catch (DataAccessException e) {if (!(e instanceof UnitTestException)) {log.info("error loading list of courses: " + e.getMessage(), e);}throw new PersistenceException("unable to get list of courses.", e);}return courses;}.... }

單元測(cè)試

我們的單元測(cè)試需要稍做更改才能使用規(guī)范。

public class CourseFinderServiceImplTest {private final Class<Specification<Course>> sClass = null;@Testpublic void testCount() {final long expected = 3;final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.count(any(sClass))).thenReturn(expected);final CourseFinderService service = new CourseFinderServiceImpl(repository);final long actual = service.count();assertEquals(expected, actual);}@Testpublic void testCountByTestRun() {final long expected = 3;final TestRun testRun = new TestRun();final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.count(any(sClass))).thenReturn(expected);final CourseFinderService service = new CourseFinderServiceImpl(repository);final long actual = service.countByTestRun(testRun);assertEquals(expected, actual);}@Test(expected = PersistenceException.class)public void testCountError() {final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.count(any(sClass))).thenThrow(new UnitTestException());final CourseFinderService service = new CourseFinderServiceImpl(repository);service.count();}@Testpublic void testFindAllCourses() {final List<Course> expected = Collections.emptyList();final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.findAll(any(sClass))).thenReturn(expected);final CourseFinderService service = new CourseFinderServiceImpl(repository);final List<Course> actual = service.findAllCourses();assertEquals(expected, actual);}@Test(expected = PersistenceException.class)public void testFindAllCoursesError() {final CourseRepository repository = Mockito.mock(CourseRepository.class);final Class<Specification<Course>> sClass = null;when(repository.findAll(any(sClass))).thenThrow(new UnitTestException());final CourseFinderService service = new CourseFinderServiceImpl(repository);service.findAllCourses();}@Testpublic void testFindCourseByTestUuid() {final TestRun testRun = new TestRun();final Course course = new Course();final List<Course> expected = Collections.singletonList(course);final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.findAll(any(sClass))).thenReturn(expected);final CourseFinderService service = new CourseFinderServiceImpl(repository);final List actual = service.findCoursesByTestRun(testRun);assertEquals(expected, actual);}@Test(expected = PersistenceException.class)public void testFindCourseByTestUuidError() {final TestRun testRun = new TestRun();final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.findAll(any(sClass))).thenThrow(new UnitTestException());final CourseFinderService service = new CourseFinderServiceImpl(repository);service.findCoursesByTestRun(testRun);}@Testpublic void testFindCoursesByTestUuid() {final TestRun testRun = new TestRun();final Course course = new Course();final List<Course> expected = Collections.singletonList(course);final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.findAll(any(sClass))).thenReturn(expected);final CourseFinderService service = new CourseFinderServiceImpl(repository);final List<Course> actual = service.findCoursesByTestRun(testRun);assertEquals(expected, actual);}@Test(expected = PersistenceException.class)public void testFindCoursesByTestUuidError() {final TestRun testRun = new TestRun();final CourseRepository repository = Mockito.mock(CourseRepository.class);when(repository.findAll(any(sClass))).thenThrow(new UnitTestException());final CourseFinderService service = new CourseFinderServiceImpl(repository);service.findCoursesByTestRun(testRun);}.... }

通過(guò)使用@Begin方法，我可以消除很多重復(fù)的代碼，但是我決定反對(duì)它來(lái)支持并行測(cè)試。

整合測(cè)試

我們終于來(lái)進(jìn)行集成測(cè)試。我們知道我們做對(duì)了，因?yàn)?strong>唯一的一行可以測(cè)試附加功能-計(jì)算數(shù)據(jù)庫(kù)中的課程數(shù)量。

@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(classes = { BusinessApplicationContext.class, TestBusinessApplicationContext.class,TestPersistenceJpaConfig.class }) @Transactional @TransactionConfiguration(defaultRollback = true) public class CourseServiceIntegrationTest {@Resourceprivate CourseFinderService fdao;@Resourceprivate CourseManagerService mdao;@Resourceprivate TestRunService testService;@Testpublic void testCourseLifecycle() throws Exception {final TestRun testRun = testService.createTestRun();final String name = "Calculus 101 : " + testRun.getUuid();final Course expected = new Course();expected.setName(name);assertNull(expected.getId());// create courseCourse actual = mdao.createCourseForTesting(name, testRun);expected.setId(actual.getId());expected.setUuid(actual.getUuid());expected.setCreationDate(actual.getCreationDate());assertThat(expected, equalTo(actual));assertNotNull(actual.getUuid());assertNotNull(actual.getCreationDate());// get course by idactual = fdao.findCourseById(expected.getId());assertThat(expected, equalTo(actual));// get course by uuidactual = fdao.findCourseByUuid(expected.getUuid());assertThat(expected, equalTo(actual));// get all coursesfinal List<Course> courses = fdao.findCoursesByTestRun(testRun);assertTrue(courses.contains(actual));// count coursesfinal long count = fdao.countByTestRun(testRun);assertTrue(count > 0);// update courseexpected.setName("Calculus 102 : " + testRun.getUuid());actual = mdao.updateCourse(actual, expected.getName());assertThat(expected, equalTo(actual));// delete Coursemdao.deleteCourse(expected.getUuid(), 0);try {fdao.findCourseByUuid(expected.getUuid());fail("exception expected");} catch (ObjectNotFoundException e) {// expected}testService.deleteTestRun(testRun.getUuid());} }

源代碼

可從http://code.google.com/p/invariant-properties-blog/source/browse/student獲取源代碼。

參考：項(xiàng)目學(xué)生： Invariant Properties博客上來(lái)自JCG合作伙伴 Bear Giles的JPA標(biāo)準(zhǔn)查詢。

翻譯自: https://www.javacodegeeks.com/2014/01/project-student-jpa-criteria-queries.html