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我正在使用休眠 3.5

实体类是

package ca.cbc.medialib.entity;


@Entity
public class Category implements Serializable {

/**
 *
 */
private static final long serialVersionUID = 7909213900961217486L;
@XmlAttribute
private long id;
@XmlElement
private String title;
@XmlElement
private String fullTitle;
@XmlElement
private String description;
@XmlElement
private String bigBoxUrl;
@XmlElement
private String bannerAdUrl;
@XmlElement
private String thumbnailUrl;
@XmlElementWrapper(name = "sponsors")
@XmlElement(name = "sponsor")
private Set<Sponsor> sponsors;
private Category parent;
@XmlElementWrapper(name = "medias")
@XmlElement(name = "media")
private List<Media> medias;
@XmlElementWrapper(name = "categories")
@XmlElement(name = "category")
private List<Category> children;

private String sortField;
private String sortOrder;

private Category() {
    children = new ArrayList<Category>();
    medias = new ArrayList<Media>();
    sponsors = new HashSet<Sponsor>();
}

public Category(long id, String title, String fullTitle, String description, String bigBoxUrl, String bannerAdUrl, String thumbnailUrl) {
    this();
    this.id = id;
    this.title = title;
    this.fullTitle = fullTitle;
    this.description = description;
    this.bigBoxUrl = bigBoxUrl;
    this.bannerAdUrl = bannerAdUrl;
    this.thumbnailUrl = thumbnailUrl;
}

public void addChild(Category child) {
    child.setParent(this);
}

public void addMedia(Media media) {
    media.addCategory(this);
}

public void addSponsor(Sponsor s) {
    this.sponsors.add(s);
}

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    Category category = (Category) o;

    if (fullTitle != null ? !fullTitle.equals(category.fullTitle) : category.fullTitle != null) return false;
    if (id != category.getId()) return false;

    return true;
}

@Column(name = "banner_ad_url")
public String getBannerAdUrl() {
    return bannerAdUrl;
}

@Column(name = "big_box_url")
public String getBigBoxUrl() {
    return bigBoxUrl;
}

@OneToMany(mappedBy = "parent")
@AccessType("field")
public List<Category> getChildren() {
    return Collections.unmodifiableList(children);
}

public String getDescription() {
    return description;
}

@Column(name = "full_title")
public String getFullTitle() {
    return fullTitle;
}

@Id
public long getId() {
    return id;
}

@ManyToMany(mappedBy = "categories")
@AccessType("field")
public List<Media> getMedias() {
    return medias;
}

@ManyToOne
@JoinColumn(name = "parent_id")
@AccessType("field")
public Category getParent() {
    return parent;
}

@Column(name = "sort_field")
public String getSortField() {
    return sortField;
}

@Column(name = "sort_order")
public String getSortOrder() {
    return sortOrder;
}

@ElementCollection
@CollectionTable(name = "sponsor", joinColumns = @JoinColumn(name = "category_id"))
@AttributeOverrides({
        @AttributeOverride(name = "imageUrl", column = @Column(name = "image_url")),
        @AttributeOverride(name = "url", column = @Column(name = "url"))})
public Set<Sponsor> getSponsors() {
    return sponsors;
}

@Column(name = "thumbnail_url")
public String getThumbnailUrl() {
    return thumbnailUrl;
}

public String getTitle() {
    return title;
}

@Override
public int hashCode() {
    int result = fullTitle != null ? fullTitle.hashCode() : (int) (id % 1000l);
    result = 31 * result;
    return result;
}

protected void internallAddMedia(Media media) {
    this.medias.add(media);
}

protected void internallRemoveMedia(Media media) {
    this.medias.remove(media);
}

public void removeChild(Category child) {
    if (children.contains(child)) {
        child.setParent(null);
    }
}

public void removeMedia(Media media) {
    media.removeCategory(this);
}


public void setBannerAdUrl(String bannerAdUrl) {
    this.bannerAdUrl = bannerAdUrl;
}

public void setBigBoxUrl(String bigBoxUrl) {
    this.bigBoxUrl = bigBoxUrl;
}

public void setDescription(String description) {
    this.description = description;
}

public void setFullTitle(String fullTitle) {
    this.fullTitle = fullTitle;
}

public void setId(long id) {
    this.id = id;
}

public void setParent(Category parent) {
    if (this.parent != null) {
        this.parent.children.remove(this);
    }
    this.parent = parent;
    if (parent != null) {
        parent.children.add(this);
    }
}

public void setSortField(String sortField) {
    this.sortField = sortField;
}

public void setSortOrder(String sortOrder) {
    this.sortOrder = sortOrder;
}

public void setSponsors(Set<Sponsor> l) {
    sponsors = l;
}

public void setThumbnailUrl(String thumbnailUrl) {
    this.thumbnailUrl = thumbnailUrl;
}

public void setTitle(String title) {
    this.title = title;
}
}

该实体与自身具有多对一关系。

我的查询方法如下所示：

public List<T> load(int first, int ps, String sortField, SortOrder sortOrder, Map<String, String> filters) {
    logger.debug("loading lazily with page size {} and first {}", ps, first);
    logger.debug("Page size is {}", getPageSize());
    Criteria criteria = HibernateUtil.getSession().createCriteria(clazz);

    if(filters != null && filters.size()!=0){

        for (Map.Entry<String, String> e : filters.entrySet()) {
            criteria.add(Restrictions.like(e.getKey(), e.getValue()+'%'));
        }
    }
    int pn = ((Long)criteria.setProjection(Projections.rowCount()).uniqueResult()).intValue();
    logger.debug("number of pages is {}", pn);
    setRowCount(pn);
    criteria.setProjection(null);

    if (sortField != null && !sortField.trim().equals("")) {
        if (sortOrder == SortOrder.DESCENDING) {
            criteria.addOrder(org.hibernate.criterion.Order.desc(sortField));
        } else {
            criteria.addOrder(Order.asc(sortField));
        }
    }


    criteria.setFirstResult(first);
    criteria.setMaxResults(first+ps);
    List<T> cats= (List<T>) criteria.list();
    logger.debug("cats found " + cats.size());
    logger.debug("first element {}", cats.get(0));
    return cats;

}

这个类的实例是用 Category 的和 clazz 构造的。问题是这个方法的返回值不是一个列表，而是一个元组列表。

通过休眠和日志跟踪执行的查询是

描述为descript4_0_0_，category2_.full_title为full5_0_0_，category2_.parent_id为parent10_0_0_，category2_.sort_field为sort6_0_0_，category2_.sort_order为sort7_0_0_，category2_.thumbnail_url为thumbnail8_0_0_，category2_.title为title0_0_ 从Category this_左外连接Category category2_ on this_。 parent_id=category2_.id 限制？2011-10-27 14:14:01,575 DEBUG [605506535@qtp-1804533116-4] [AbstractBatcher.java:426]：即将打开 ResultSet（打开 ResultSets：0，全局：0）2011-10-27 14:14 ：01,577 调试 [605506535@qtp-1804533116-4] [Loader.java:1322]：结果行：null，EntityKey [ca.cbc.medialib.entity.Category#1] 2011-10-27 14:14:01,581 调试[605506535@qtp-1804533116-4] [Loader.java:1322]：结果行：

4

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