Apache Avro：map使用CharSequence作为密钥 [英] Apache Avro: map uses CharSequence as key

问题描述

我正在使用 Apache Avro 。

我的架构有地图类型：

{"name": "MyData", 
  "type" :  {"type": "map", 
              "values":{
                   "type": "record",
                   "name": "Person",
                   "fields":[
                      {"name": "name", "type": "string"},
                      {"name": "age", "type": "int"},

                ]
                }
               }
}

编译架构后，生成的Java类使用 CharSequence 作为 Map 键 c $ c> MyData 。

After compile the schema, the genated Java class use CharSequence as the key for the Map MyData.

在地图中使用 CharSequence 非常不方便作为键，有没有办法在 Map 生成 String 类型键avro.apache.org/docs/1.7.5/gettingstartedjava.html\"rel =nofollow> Apache Avro ？

It is very inconvenient to use CharSequence in Map as key, is there a way to generate String type key for Map in Apache Avro?

PS

问题是，例如 dataMap.containsKey（SOME_KEY）将返回 false 即使那里有这样的密钥，只是因为它是 CharSequence 。此外，使用现有密钥放置映射条目不会重新使用旧密钥。这就是为什么我说使用 CharSequence 作为密钥是不方便的。

Problem is that, for example dataMap.containsKey("SOME_KEY") will returns false even though there is such key there, just because it is CharSequence. Besides, put an map entry with a existing key doesn't relpace the old one. That's why I say it is inconvenient to use CharSequence as key.

推荐答案

此JIRA讨论是相关的。仍然使用CharSequence的要点是向后兼容性。

This JIRA discussion is relevant. The main point of CharSequence still being used is backwards-compatability.

和Charles Forsythe指出的一样，通过在模式中设置字符串属性，已经为必要时添加了一个变通方法。

And like Charles Forsythe pointed out, there has been added a workaround for when String is necessary, by setting the string property in the schema.

 { "type": "string", "avro.java.string": "String" }

这里的默认类型是他们自己的Utf8类。除了手动规范和 pom.xml设置，甚至有一个avro-tools编译选项， -string 选项：

The default type here is their own Utf8 class. In addition to manual specification and the pom.xml setting, there is even an avro-tools compile option for it, the -string option:

java -jar avro-tools.1.7.5.jar compile -string schema /path/to/schema .

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