用于Voldemort中任意HashMaps的JSON序列化程序

问题描述

我试图设置Voldemort键值存储的配置。现在，我希望能够存储任意hashmaps，但我还没有找到这样做的方法（或者如果可能的话）。

根据文档，我应该使用以下语法：

  {fname：string，lname：string ，id：int32，emails：[string]} 
  

我想存储一个Java bean的HashMap表示，但是对允许的键有限制（只有 fname ， lname ， id 和电子邮件）及其类型。

我需要的是能够存储一个像这样的任意地图：

  {name：fred， ID：15} 
  

或者像这样：

  {apples：50 $，oranges：15€} 
  

（地图数值没有意义，仅仅是带有不同关键字名称和值类型的地图的示例）

有没有办法定义一个可以接受的模式一个任意的散列表？

解决方案

我发现有用的是只使用通用原始存储（通过byte []）并在客户端预先序列化事物。这是微不足道的（我使用）：

  ObjectMapper mapper = new ObjectMapper（）; 
 //存储：
 byte [] data = mapper.writeValueAsBytes（myMap）; 
 //以及取回时：
 Map< String，Object> data = mapper.readValue（data，Map.class）; 
  

虽然Voldemort确实支持其类似JSON的存储（它不是JSON，而是简单的二进制字典，据我所知，使用它没有多大好处，因为你无法查询它或请求文档的子集。

I am trying to set up the configuration for Voldemort key-value store. Now, I'd like to be able to store arbitrary hashmaps in it, but I haven't found the way to do so (or if it is possible).

According to the documentation I should use this syntax:

{"fname":"string", "lname":"string", "id":"int32", "emails":["string"]}

To indicate that I want to store a HashMap representation of a Java bean, but with constraints on allowed keys (only fname,lname,id and emails) and their types.

What I would need is to be able to store an arbitrary map like this:

{"name":"fred", "id":15}

or like this:

{"apples":"50$", "oranges":"15€"}

(Map values are meaningless, just an illustration of maps with different key names, and value types)

Is there a way to define a schema that would accept an arbitrary hashmap?

解决方案

What I have found useful is to just use generic raw storage (where byte[] is passed), and pre-serializing things on client side. This is trivial to use (I use Jackson):

  ObjectMapper mapper = new ObjectMapper();
  // to store:
  byte[] data = mapper.writeValueAsBytes(myMap);
  // and when retrieving back:
  Map<String,Object> data = mapper.readValue(data, Map.class);

While Voldemort does support its "JSON-like" storage (it's not JSON but simple binary dictionaries, as far as I know), there isn't much benefit to using it in my opinion, since you can not query on it or request subsets of document.

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