如何将投影应用于Spring Data REST查询方法资源？ [英] How do I apply a projection to a Spring Data REST query method resource?

问题描述

我正在使用Spring Data REST 2.1.4.RELEASE。

I'm using Spring Data REST 2.1.4.RELEASE.

我创建了

• 一个实体预订，


• 其REST存储库（扩展 CrudRepository ）名为 BookingRepository


• 和投影 BookingDetails （注释为 @Projection（name =details，types = Booking.class））用于返回部分爆炸的链接实体，例如资源，活动，申请人等。

• an entity Booking,
• its REST repository (extending CrudRepository) named BookingRepository
• and a projection BookingDetails (annotated with @Projection(name="details", types = Booking.class)) for returning some of its linked entities exploded, such as Resource, Activity, Applicant etc.

客户通过 ... / rest / bookings 获取所有预订，JSON响应包含链接的链接实体。如果它添加？projection = details ，则会展开并返回链接的实体。这很棒。

The client gets all bookings with .../rest/bookings and the JSON response includes links for the linked entities. If it adds ?projection=details then the linked entities are exploded and returned. And this is great.

现在我将自定义方法添加到存储库中：

Now I add this custom method to the repository:

List<Booking> findByApplicant(@Param("applicant") Person applicant);

当客户使用 ... / rest / bookings / search调用它时/ findByApplicant？applicant = 5 ，似乎无法请求详细信息投影。以下尝试将被忽略：

When the client invokes it with .../rest/bookings/search/findByApplicant?applicant=5, there seem to be no way to request the details projection. Following attempts are ignored:

• 将& projection = details 添加到查询字符串



• 使方法始终返回 BookingDetails ：

List<BookingDetails> findByApplicant(@Param("applicant") Person applicant);

汇总，自定义搜索方法（ findBy * ）永远不会返回投影。除非您使用 @RepositoryRestResource（excerptProjection = BookingDetails.class）注释存储库，但这会导致一些问题，首先客户端必须始终使用相同的投影。我们如何允许用户使用 findBy * 方法进行投影？

Summarizing, custom search methods (findBy*) never return a projection. Unless you annotate the repository with @RepositoryRestResource(excerptProjection = BookingDetails.class), but this leads to some problems, first of all the client has to always use the same projection. How can we allow the user to use projections also with findBy* methods?

推荐答案

我使用Spring Data REST 2.2.1验证了这一点，所以请更新它。确保您的客户端实际发送所需的参数。在调试时，我发现了如果您没有显式引用URI，则cURL会删除查询参数。所以这个：

I verfied this working with Spring Data REST 2.2.1, so please update it. Make sure your client actually sends the the requested parameters as you intend. While debugging, I found out that e.g. cURL drops query parameters if you do not explicitly quote the URI. So this:

curl http://localhost:8080/orders/search/findByApplicant?applicant=5&projection=details

将不发送任何查询参数。一旦引用URI，它就会。

will not send any of the query parameters. Once you quote the URI, it will.

curl 'http://localhost:8080/orders/search/findByApplicant?applicant=5&projection=details'

对于日益流行的 HTTPie 。有了它，所需的语法是：

Sort of the same is in place for the increasingly popular HTTPie. With it the required syntax is:

http :8080/orders/search/findByApplicant applicant==5 projection==details

如果你无法以这种方式工作，那么获得一个正在运行的示例项目会很酷看看。

In case you can't get it to work that way, it would be cool to get a running example project to look at.

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