无法使用物化获取保存的实体 [英] Unable to get saved entity using objectify

问题描述

我无法使用Objectify获得可靠的实体。

看起来缓存已损坏。奇怪的是 - 我可以通过管理控制台数据存储查看器正确看到保存的实体。我还编写了一个小程序来查看使用RemoteApi的实体，我可以正确地看到保存的值。

当我使用servlet或云端点rest api连续查询实体时 - 我的连续查询给出了不同的结果，并且它看起来像数据存储区/缓存中的某个

我的实体看起来像这样。

  class ContentEntity {
 @Id Long id; 
 String html; 
 @Index字符串标签; 
布尔publish; 
} 
  

我将它保存为这样。

  ContentEntity entity = ofy（）。load.type（ContentEntity.class）
 .filter（tag，my tag）。first（）。得到（）; 
 
 if（null == entity）
 entity = new ContentEntity（）; 
 
 entity.html =我的html; 
 entity.tag =我的标签; 
 entity.publish = true; 
 
 ofy（）。save.entity（entity）.now（）; 
  

我像这样检索它。

<$ p $（p> ContentEntity entity = ofy（）。load（）.type（ContentEntity.class）。
filter（tag，my tag）。first（）。get（）;


会发生什么如下 -

1）让ContentEntity.html的初始值为值1

2）使用管理控制台数据存储区查看器保存新值 - 值2

我可以看到值2被正确保存。 （使用远程API也可以看到值2）

3）使用上面粘贴的检索代码通过servlet或rest api查看实体。我看到value 2

4）通过servlet或rest api再次查看实体。我看到价值1

5）再次查看。我看到价值2

它继续在价值1和价值2之间切换

这一切在我的工作很好开发环境，但不在appengine中。

看起来我正在做错事，并且没有正确处理最终的一致性。我总是希望得到一致的结果。如果我的查询速度稍慢，我不介意。我应该怎么办？

任何提示/建议/帮助将不胜感激。

p>

Sathya

解决方案

事实证明，这是因为我忘记了添加在物理化wiki页面中提到的web.xml中的物化过滤器

我在web.xml中添加了以下内容，问题解决了。

 <滤光器> 
< filter-name> ObjectifyFilter< / filter-name> 
< filter-class> com.googlecode.objectify.ObjectifyFilter< / filter-class> 
< / filter> 
< filter-mapping> 
< filter-name> ObjectifyFilter< / filter-name> 
< url-pattern> / *< / url-pattern> 
< / filter-mapping> b 
 
 
 
 
 
 > 
I am unable to get my saved entity reliably using Objectify. 

It looks like the cache is getting corrupted. The strange thing is - I can see the saved entity correctly though admin console datastore viewer. Also I wrote a small program to view the entity using RemoteApi and I can see the saved value correctly. 

When I query the entity successively using a servlet or a cloud endpoint rest api - my successive queries are giving different results, and it looks like something in the datastore/cache is getting corrupted.

My entity looks like this.
class ContentEntity {
  @Id Long id;
  String html;
  @Index String tag;
  boolean publish;
}
I save it like this.
ContentEntity entity = ofy().load.type(ContentEntity.class)
    .filter("tag", "my tag").first().get();

if (null == entity)
    entity = new ContentEntity();

entity.html = "my html";
entity.tag = "my tag";
entity.publish = true;

ofy().save.entity(entity).now();
I retreive it like this.
ContentEntity entity = ofy().load().type(ContentEntity.class).
            filter("tag", "my tag").first().get();
What happens is as follows -

1) Let the intial value of ContentEntity.html be "value 1" 

2) save a new value - "value 2" 

3) using admin console datastore viewer I can see "value 2" is saved correctly. (using remote api also I can see "value 2") 

3) View the entity through servlet or rest api using the retrieve code pasted above. I see "value 2" 

4) View the entity again through servlet or rest api. I see "value 1" 

5) View it again. I see "value 2" 

it keeps switching between "value 1" and "value 2" 


It all worked fine in my dev environment but not in appengine.

Looks like I am doing something wrong and not handling eventual consistency correctly. I always want strongly consistent results. I don't mind if my queries are little slower. What should I do ?

Any tips/suggestions/help would be much appreciated.

Regards,

Sathya
解决方案
It turns out this is because I had forgotten to add objectify filter in web.xml as mentioned in Objectify wiki page

I added the following in my web.xml and the problem was solved.
<filter>
    <filter-name>ObjectifyFilter</filter-name>
    <filter-class>com.googlecode.objectify.ObjectifyFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>ObjectifyFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
Regards,

Sathya

                        
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