Spring Data Rest Pageable子集合 [英] Spring Data Rest Pageable Child Collection

问题描述

我有一个名为User的@Entity。它有一组变化集，如下所示：

  @OneToMany（fetch = FetchType.LAZY，cascade = CascadeType.ALL，mappedBy = user）
 private Set< Changeset> changesets = new HashSet< Changeset>（）; 
  

我有一个UserRepository：

  @Repository 
 @RestResource（path =users，rel =users）
 public interface UserRepository扩展JpaRepository< User，Long> {} 
  

和一个ChangesetRepository：

  @Repository 
 @RestResource（path =changesets，rel =changesets）
 public interface ChangesetRepository extends JpaRepository< Changeset，Long> {
  

在 http：// localhost：8080 / changesets / 或 http：// localhost：8080 / users / 会产生一个分页回应。

如果我在 http：// localhost：8080 / users / 1 / changesets 上调用GET，那么我将所有结果都放在一个数组中，不会发生分页。

有没有一种方法可以向Spring Data Rest表明我想通过其父级用户访问它时以可分页方式返回changesets集合？这组变化集会快速增长，我宁愿不会在单个页面中返回大量结果。

编辑：

正如Willie Wheeler所建议的那样，我将此添加到我的ChangesetRepository中以使其可搜索：

  @RestResource（path = byUser，rel =byUser）
 public Page< Changeset> findByUser（@Param（id）用户用户，Pageable p）; 
  

我使用双向关系，但也可以隐藏用户的变更集链接 @RestResource（exported = false）在变更集上。

方面注意：到exported = false隐藏链接，但不实际删除映射。 / users / 1 / changesets不会被公布，但它仍然有效。

解决方案

我不认为SDR直接支持你描述的方法。

你还可以采取另一种方法。而不是使用 Person 和 Changeset 之间的双向关系，使它从 Changeset 到 Person 。然后在你的 ChangesetRepository 中包含这样一个方法： path =按人物查找）
页面<变更集> findByPerson（@Param（person）Person person，Pageable pageable）;

（我只是从内存中执行此操作，因此您可能需要稍作调整。）

从设计的角度来看，我认为这是更强大的，因为我认为一个人的变化集在少数情况下是相关的。查询变更集而不是将其与人员捆绑在一起可能更合适。

I have an @Entity called User. It has a Set of Changesets as follows:

@OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.ALL, mappedBy="user")
private Set<Changeset> changesets = new HashSet<Changeset>();

I have a UserRepository:

@Repository
@RestResource(path = "users", rel = "users")
public interface UserRepository extends JpaRepository<User, Long>{ }

And a ChangesetRepository:

@Repository
@RestResource(path = "changesets", rel = "changesets")
public interface ChangesetRepository extends JpaRepository<Changeset, Long> { }

Calling GET on http://localhost:8080/changesets/ or http://localhost:8080/users/ yields a paged response.

If I call GET on http://localhost:8080/users/1/changesets then I get all the results in a single array and no paging occurs.

Is there a way to indicate to Spring Data Rest that I want to return the changesets collection in a pageable manner when accessing it through its parent User? The Set of changesets will grow quickly and I'd rather not return tons of results in a single page.

EDIT:

As suggested by Willie Wheeler I added this to my ChangesetRepository to make it searchable:

@RestResource(path = "byUser", rel = "byUser")
public Page<Changeset> findByUser(@Param("id") User user, Pageable p);

I left the relationship bidirectional, but was also able to hide the link to changesets from a user by using @RestResource(exported=false) on the Set of changesets.

Side Note: It appears that setting the relationship to exported=false hides the link, but doesn't actually remove the mapping. /users/1/changesets isn't advertised, but it's still valid.

解决方案

I don't think that SDR directly supports the approach you describe.

There's another approach you might take though. Instead of using a bidirectional relationship between Person and Changeset, make it unidirectional from the Changeset to the Person. Then in your ChangesetRepository include a method like this:

@RestResource(path = "find-by-person")
Page<Changeset> findByPerson(@Param("person") Person person, Pageable pageable);

(I'm just doing that from memory, so you might require minor adjustments.)

From a design perspective I think this is stronger anyway, since I imagine that a person's changesets are relevant in a limited number of contexts. It might be more appropriate to query for changesets rather than bundling them with the person.

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