jdo,gae:按子键加载对象组

xyhw6mcr  于 2021-07-05  发布在  Java
关注(0)|答案(1)|浏览(328)

我拥有两个对象之间的一对多关系:

@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class AccessInfo {
    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private com.google.appengine.api.datastore.Key keyInternal;     
    ...     
    @Persistent
    private PollInfo currentState;

    public AccessInfo(){}

    public AccessInfo(String key, String voter, PollInfo currentState) {
        this.voter = voter;
        this.currentState = currentState;
        setKey(key); // this key is unique in whole systme
    }

    public void setKey(String key) {
        this.keyInternal = KeyFactory.createKey(
                AccessInfo.class.getSimpleName(),
                key);
    }

    public String getKey() {
        return this.keyInternal.getName();
    }

以及

@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class PollInfo
{
    @PrimaryKey
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private Key key;

    @Persistent(mappedBy = "currentState")
    private List<AccessInfo> accesses;
    ...

我创建了一个类pollinfo的示例并使其持久化。没关系。但是我想通过accessinfo键加载这个组,得到异常nucleusobjectnotfoundexception。是否可以按孩子的键加载组?

rqenqsqc

rqenqsqc1#

如果您引用检索accessinfo对象的代码,以及如何获得所使用的“密钥”?

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