Spring-Roo JPA创建的实体未更新

Question

I'm working on code from the book 'Spring Roo in Action', and I'm running into a problem. As per the book, I am generating two JPA entities, Offering and Course; course to offering is a one-to-many dependency.

Using the Roo command shell, I have generated the relationship between the two entities thus:

focus --class ~.model.Course

field set --fieldName offerings --type ~.model.Offering --cardinality ONE_TO_MANY --mappedBy "course"

focus --class ~.model.Offering

field reference --fieldName course --type ~.model.Course --cardinality MANY_TO_ONE

This has generated the class code Offering with annotations:

@RooJavaBean
@RooToString
@RooJpaActiveRecord
public class Offering {
/**
 */
@NotNull
@Temporal(TemporalType.TIMESTAMP)
@DateTimeFormat(style = "M-")
private Date offerDate;

/**
 */
@NotNull
@Size(min = 1, max = 80)
private String locationName;

/**
 */
@ManyToOne
private Course course;

}

And class code for Course:

@RooJavaBean
@RooToString
@RooJpaActiveRecord
public class Course {

    /**
     */
    private String name;

    /**
     */
    private BigDecimal listPrice;

    /**
     */
    private String description;

    /**
     */
    private Integer maximumCapacity;

    /**
     */
    @Temporal(TemporalType.DATE)
    @DateTimeFormat(style = "S-")
    private Date runDate;

    /**
     */
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "course")
    private Set<Offering> offerings = new HashSet<Offering>();

    /**
     */
    @ManyToOne
    private TrainingProgram trainingProgram;
}

Now, when I run the integration test , it fails, it seems that the Course is persisted, but the Offering isn't. One Offer should have been persisted and then retrieved from the database, but none are returned:

    @Test
    public void addCourseAndOffering(){
        CourseDataOnDemand courseDod = new CourseDataOnDemand();
        Course course = courseDod.getNewTransientCourse(0);
        course.setListPrice(new BigDecimal("100.00"));

        OfferingDataOnDemand offerDod = new OfferingDataOnDemand();
        Offering offer = offerDod.getNewTransientOffering(0);

        course.getOfferings().add(offer);

        course.persist();
        course.flush();
        course.clear();

        Course persistedCourse = Course.findCourse(course.getId());
        Assert.assertNotNull(persistedCourse.getId());
        Assert.assertEquals(course.getListPrice(), persistedCourse.getListPrice());
        Set<Offering> offers = persistedCourse.getOfferings();
        int size = offers.size();
        Assert.assertEquals(1, persistedCourse.getOfferings().size());
    }
}

Assertion Failure

Could somebody please advise what I am doing wrong here?

Answer 1

Try to set offer.course before persist: In JPA handle bidirectional relations should be done by application, not by library implementation. See this page [ Getters and Setters section] )

As the relationship is bi-directional so as the application updates one side of the relationship, the other side should also get updated, and be in sync. In JPA , as in Java in general it is the responsibility of the application, or the object model to maintain relationships . If your application adds to one side of a relationship, then it must add to the other side.

So try this:

@Test
public void addCourseAndOffering(){
    CourseDataOnDemand courseDod = new CourseDataOnDemand();
    Course course = courseDod.getNewTransientCourse(0);
    course.setListPrice(new BigDecimal("100.00"));

    OfferingDataOnDemand offerDod = new OfferingDataOnDemand();
    Offering offer = offerDod.getNewTransientOffering(0);

    course.getOfferings().add(offer);

    // ==================================
    offer.setCourse(course); // XXX set the offer-side relationship part
    // ==================================

    course.persist();
    course.flush();
    course.clear();

    Course persistedCourse = Course.findCourse(course.getId());
    Assert.assertNotNull(persistedCourse.getId());
    Assert.assertEquals(course.getListPrice(), persistedCourse.getListPrice());
    Set<Offering> offers = persistedCourse.getOfferings();
    int size = offers.size();
    Assert.assertEquals(1, persistedCourse.getOfferings().size());
}

Good luck!