Spring Data 在 nGrinder 当中的应用

        相对于iBatis,Spring Data更容易支持动态查询。本文将简单介绍一下其在nGrinder中的应用。

        本例中会用到nGrinder 代码中的  测试项目类  PerfTest.java

/**
 * Peformance Test Entity
 *
 */
@Entity
@Table(name = "PERF_TEST")
public class PerfTest extends BaseModel<PerfTest> {
 
    /**
     * UUID
     */
    private static final long serialVersionUID = 1369809450686098944L;
 
    @Column(name = "name")
    private String name;
 
    @Column(length = 2048)
    private String description;
 
    @Enumerated(EnumType.STRING)
    private Status status = Status.READY;
...
}

如今想作一个查询，条件是全部状态为 （FINISHED, ENDED）的测试项目

若是用SQL语句实现为

select * from perf_test where status in (‘FINISHED’, ‘ENDED’)

为了代码更有延伸性，咱们在 PerfTestRepository加入了  JpaSpecificationExecutor<PerfTest>

import java.util.List;
 
import org.ngrinder.perftest.model.PerfTest;
import org.ngrinder.perftest.model.Status;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 
 
public interface PerfTestRepository extends JpaRepository<PerfTest, Integer>, JpaSpecificationExecutor<PerfTest> {
    List<PerfTest> findAllByStatusOrderByCreateDateAsc(Status status);
 
}

在PerfTestRepository中会有经常使用的方法

/**
     * Returns a single entity matching the given {@link Specification}.
     *
     * @param spec
     * @return
     */
    T findOne(Specification<T> spec);
 
    /**
     * Returns all entities matching the given {@link Specification}.
     *
     * @param spec
     * @return
     */
    List<T> findAll(Specification<T> spec);
 
    /**
     * Returns a {@link Page} of entities matching the given {@link Specification}.
     *
     * @param spec
     * @param pageable
     * @return
     */
    Page<T> findAll(Specification<T> spec, Pageable pageable);
 
    /**
     * Returns all entities matching the given {@link Specification} and {@link Sort}.
     *
     * @param spec
     * @param sort
     * @return
     */
    List<T> findAll(Specification<T> spec, Sort sort);
 
    /**
     * Returns the number of instances that the given {@link Specification} will return.
     *
     * @param spec the {@link Specification} to count instances for
     * @return the number of instances
     */
    long count(Specification<T> spec);

这些方法会根据对应的 查询规范（Specification）动态的生成SQL语句，如下为在PerfTest中加入的“ 查询规范”

/**
 * Peformance Test Entity
 *
 */
@Entity
@Table(name = "PERF_TEST")
public class PerfTest extends BaseModel<PerfTest> {
      ....
 
    public static Specification<PerfTest> statusSetEqual(final Status... statuses) {
        return new Specification<PerfTest>() {
            @Override
             
            public Predicate toPredicate(Root<PerfTest> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                return cb.not(root.get("status").in((Object[]) statuses));
            }
        };
 
    }
}

下面会测试代码

public class PerfTestRepositoryTest extends NGrinderIocTransactionalTestBase {
 
    @Autowired
    public PerfTestRepository repo;
 
    @Before
    public void before() {
        PerfTest entity = new PerfTest();
        entity.setStatus(Status.FINISHED);
        repo.save(entity);
        PerfTest entity2 = new PerfTest();
        entity2.setStatus(Status.CANCELED);
        repo.save(entity2);
        PerfTest entity3 = new PerfTest();
        entity3.setStatus(Status.READY);
        repo.save(entity3);
    }
 
    @Test
    public void testPerfTest() {
        List<PerfTest> findAll = repo.findAll(PerfTest.statusSetEqual(Status.FINISHED, Status.CANCELED));
        assertThat(findAll.size(), is(2));
    }
}