0

我有一个对象 PictureBook ，其中包含一个带有持久性注释的 List< Picture> 。

@PersistenceCapable(identityType = IdentityType.APPLICATION,
    detachable = "true")
public class PictureBook {


/**
 * primary key - type encoded String
 */
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName = "datanucleus", key = "gae.encoded-pk", value = "true")
private String key;

@Persistent
private String name;

@Persistent
private String creator;

@Persistent
private String link;

@Persistent
private String cover;

@Persistent(mappedBy = "pictureBook")
private List<Picture> pictures;

图片类有对pict​​ureBook类的引用

@PersistenceCapable(identityType = IdentityType.APPLICATION,
    detachable = "true")
public class Picture implements Serializable {


/**
 * primary key - type encoded String
 */
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName = "datanucleus", key = "gae.encoded-pk", value = "true")
private String key;

@Persistent
private String albumName;

@Persistent
private String creator;

@Persistent
private String link;

@Persistent
private PictureBook pictureBook;

public Picture() {
}

public Picture(String albumName, String creator, String link) {
    this.albumName = albumName;
    this.creator = creator;
    this.link = link;
}

在本地测试时，一切都按预期进行，但是当我部署到 appengine 时，我得到一个异常，告诉“xxx 类型的对象和身份 yyy 没有正确分离”。当我查询我的所有 PictureBook 实体时，我得到了这个。任何人都可以帮助我我真的坚持这个：/查询的方法如下：

    public List<PictureBook> getAllPictureBooks() {
    log.info("retrieving all PictureBooks from datastore...");
    PersistenceManager persistenceManager = PMF.getInstance().getPersistenceManager();
    Query retrieveAllPictureBooks = persistenceManager.newQuery(PictureBook.class);
    List<PictureBook> albumList = null;
    List<PictureBook> albums = null;
    try {
        albumList = (List<PictureBook>) retrieveAllPictureBooks.execute();
                    for(PictureBook pictureBook: albumList){
                            System.out.println(pictureBook.getPictures().size());
                    }
        albums = (List<PictureBook>)persistenceManager.detachCopyAll(albumList);
    } catch (Exception e) {
        log.error("an exception occured: \n" + e.getMessage());
    } finally {
        if (persistenceManager != null) {
            persistenceManager.close();
            log.info("persistenceManager closed");
        }
    }
    return albums;
}
4

1 回答 1

0

将图画书实体中的图片添加到默认获取组中修复了它

于 2013-01-14T07:53:28.580 回答