在基于Android-Studio的项目中为AppEngine创建综合索引

问题描述

我使用Android Studio创建了一个Android项目，以及它的后端AppEngine Endpoints对应项。我有一个我正在使用Objectify的数据存储。系统运行良好，直到我添加了一个过滤器到我的查询（仅显示特定给定的电子邮件）。

 查询< Report>查询= ofy（）。load（）。type（Report.class）.filter（email，user.getEmail（））。order（email）。order（ -  when）。limit（limit）; 
  

这是POJO数据存储实体：

  @Entity 
 public class Report {
 @Id 
 Long id; 
 
字符串谁; 
 
 @Index 
日期; 
 
字符串是什么; 
 
 @Index 
字符串电子邮件; 
} 
  

但是，我试图在Google API Explorer中收到这样的错误测试它：

  com.google.appengine.api.datastore.DatastoreNeedIndexException：找不到匹配的索引。 
此查询的建议索引是：
  < property name = \when \direction = \desc\/> 
< / datastore-index> 
  

据我所知，我只需创建一个包含特定字段email和when的复合索引，不过，我发现的大多数文档都告诉我要编辑 datastore-indexes.xml 。

不幸的是，这个文件似乎并不存在于我的项目中的任何地方。

创建datastore-indexes.xml文件

创建datastore-indexes.xml文件并放在 / WEB-INF / 文件夹中。内容将如下所示：

 < datastore-indexes 
 autoGenerate =true> 
 
  < property name = \when \direction = \desc\/> 
< / datastore-index> 
< / datastore-indexes> 
  

I used Android Studio to create both an Android project, and its backend AppEngine Endpoints counterpart. I have a datastore for which I am using Objectify. The system worked great, until I added a filter to my Query (to show only specific given emails).

Query<Report> query = ofy().load().type(Report.class).filter("email", user.getEmail()).order("email").order("-when").limit(limit);

This is the POJO Datastore Entity:

@Entity
public class Report {
    @Id
    Long id;

    String who;

    @Index
    Date when;

    String what;

    @Index
    String email;
}

However, I receive such an error from the Google API Explorer when I attempt to test it:

com.google.appengine.api.datastore.DatastoreNeedIndexException: no matching index found.
The suggested index for this query is:
    <datastore-index kind=\"AccessReport\" ancestor=\"false\" source=\"manual\">
    <property name=\"email\" direction=\"asc\"/>
    <property name=\"when\" direction=\"desc\"/>
    </datastore-index>

As I understand it, I simply need to create a composite index including the specific fields email and when, with their specific sort direction.

However, most documentation that I find tell me to edit datastore-indexes.xml.

Unfortunately, this file does not seem to exist anywhere in my project.

Is anyone familiar with the way to change this when working with Android Studio?

解决方案

Create datastore-indexes.xml file and put it in /WEB-INF/ folder. The content will look like this:

<datastore-indexes
  autoGenerate="true">

    <datastore-index kind=\"AccessReport\" ancestor=\"false\" source=\"manual\">
        <property name=\"email\" direction=\"asc\"/>
        <property name=\"when\" direction=\"desc\"/>
    </datastore-index>
</datastore-indexes>

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