Question

我的代码结构如下所示。

文章：

@Entity
public class NewsArticle{

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;

    [Other class properties such as title, publisher, publishedDate, etc.]        

    @OneToMany(mappedBy = "article")
    private Set<UserReadNewsArticle> userReadNewsArticles = new HashSet<>();

    [Getters and Setters]
}

用户阅读的文章：

@Entity
public class UserReadNewsArticle {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;

    private Long readAccountId;    
    private Long readArticleId;           

    @JsonIgnore
    @ManyToOne
    private Account account;

    @JsonIgnore
    @ManyToOne
    private NewsArticle article;

    [Getters and Setters]


}

帐户：

@Entity
public class Account {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;

    [Other class properties]

    @OneToMany(mappedBy = "account")
    private Set<UserReadNewsArticle> userReadNewsArticles = new HashSet<>();

    [Getters and Setters]
}

我希望在我的NewsArticleRepository中有一个查询方法来获取用户的所有阅读新闻文章。

public interface NewsArticleRepository extends PagingAndSortingRepository<NewsArticle, Long>{

    Collection<NewsArticle> findByUserReadNewsArticlesReadAccountId(Long readAccountId);

}

这种方法效果很好。但是如何编写Spring Data JPA查询/方法来为用户获取＆＃34;未读新闻文章＆＃34;。我试过的是以下内容。

Collection<NewsArticle> findByUserReadNewsArticlesReadAccountIdNot(Long readAccountId);

这个确实返回了其他用户已阅读的文章列表。但我的要求是获取所有未读的新闻文章。我经历过Spring Data JPA Documentation但未能提出更容易的灵魂。我怎样才能克服这个问题？或者我做错了什么？

Answer 1

您可以通过使用带有子查询的JPQL查询来实现结果：

def loss(self,X,y,reg = 0.0):
    #forward prop
    W1, b1 = self.params['W1'], self.params['b1']
    W2, b2 = self.params['W2'], self.params['b2']
    W3, b3 = self.params['W3'], self.params['b3']
    N,D = X.shape
    H1out = np.maximum(0,X.dot(W1)+b1)        #H1out (N,H1)
    H2out = np.maximum(0,H1out.dot(W2)+b2)    #H2out (N,H2)
    scores = None
    scores = H2out.dot(W3)+b3
    scores_shift = scores-np.max(scores,axis = 1).reshape(-1,1)
    softmaxout = np.exp(scores_shift)/np.sum(np.exp(scores_shift),axis=1).reshape(-1,1)
    loss_main = None
    loss = None
    loss_main = -np.sum(np.log(softmaxout[range(N),list(y)]))
    loss = loss_main/N + reg*np.sum(W1*W1)*np.sum(
            W2*W2)+np.sum(W3*W3)

    #backward prop
    dscores = softmaxout.copy()               #dscores (N,C)
    dscores[range(N),list(y)] -= 1
    dscores /= N

    dW3 = H2out.T.dot(dscores)
    db3 = np.sum(dscores,axis = 0)

    dh2 = dscores.dot(W3.T)                   #dh2 (N,H2)
    dh_Relu2 = (H2out > 0) * dh2              #dh_ReLu2 (N,H2)
    dW2 = H1out.T.dot(dh_Relu2)
    db2 = np.sum(dh_Relu2,axis = 0)

    dh1 = dh_Relu2.dot(W2.T)                  #dh1 (N,H1)
    dh_Relu1 = (H1out>0) * dh1
    dW1 = X.T.dot(dh_Relu1)
    db1 = np.sum(dh_Relu1,axis = 0)

    grad = {}
    grad['W1'] = dW1
    grad['b1'] = db1
    grad['W2'] = dW2
    grad['b2'] = db2
    grad['W3'] = dW3
    grad['b3'] = db3

    return loss,grad

http://localhost:8080/newsArticles/search/findByUserReadNewsArticlesReadAccountIdNotIn?readAccountId=1

首先从当前用户那里获取阅读清晰度，然后将其从整篇文章列表中排除。

我不认为spring数据能够让你变得一样，因为子查询是绝对需要的。如果我错了，有人可以纠正我。

Spring Data JPA Query

1 个答案: