如何在Java中将JSON数组转换为RDF? [英] How to convert JSON array to RDF in Java?

问题描述

我想将JSON(不是JSON-LD)数组转换为Java中的RDF.我在论坛上看到过类似的帖子，但没有确切的答案. JSON数组包含对象和数组，例如:

I want to convert a JSON (not JSON-LD) array to RDF in Java. I have seen similar posts to the forum but not exact answer. The JSON array contains objects and arrays, something like:

{
   "results": [
      {
         "record_id": "3d87f4df-f17e-4632-9449",
         "demographics": { "gender":"female", "race":"", "age":20 }
      },
      {
         "record_id": "ec5ca92d-865a-431f-9984",
         "demographics": { "gender":"male", "age":118 }
      },
      {
         "record_id": "0a79ecf0-83d8-4148-9054",
         "demographics": { "gender":"female", "age":118 }
      },
      {
         "record_id": "229276f8-1893-480b-b6e7",
         "demographics": { "gender":"female", "age":35 }
      },
      {
         "record_id": "0574cc3b-fb9c-495f-851c",
         "demographics": { "gender":"female", "age":40 }
      },
      {
         "record_id": "f3ccfdf6-231e-4a3e-bee0",
         "demographics": { "gender":"male", "age":118 }
      }
   ]
}

有什么想法吗? 谢谢！

Any ideas? Thanx!

推荐答案

我建议您不要对转换进行硬编码.

I'd suggest you not hardcoding this conversion.

对于RDBMS源(顺便说一句，为什么不使用它们)，有W3C标准化的 R2RML ( r2rml ).
对于JSON和XML源，有 RML ，它是R2RML的非正式扩展.

For RDBMS sources (by the way, why not use them), there is W3C-standardized R2RML (r2rml).
For JSON and XML sources, there is RML, an unofficial extension of R2RML.

RML映射器是RML的Java实现:

RML Mapper is a Java implementation of RML:

$ bin/RML-Mapper -m ~/Desktop/mappings.ttl -o ~/Desktop/results.ttl

通常，应将rml:iterator "$.results.[*]"放在rml:logicalSource部分中，以遍历数组元素.确切的答案取决于您要使用哪些词汇表以及要实现的数据模型.

In general, you should place rml:iterator "$.results.[*]" in the rml:logicalSource section to iterate over array elements. The exact answer depends on which vocabularies you want to use and the data model you want to achieve.

让我们假设您需要这样的东西:

Let's suppose you need something like this:

@prefix exr: <http://example.org/resource/> .
@prefix exo: <http://example.org/ontology/> .

exr:gender_female
  a exo:Gender ;
  rdfs:label "female" .

exr:gender_male
  a exo:Gender ;
  rdfs:label "male" .

exr:record_3d87f4df-f17e-4632-9449
  a exo:Record ;
  exo:patient_age 20 ;
  exo:patient_gender exo:gender_female .

exr:record_ec5ca92d-865a-431f-9984
  a exo:Record ;
  exo:patient_age 118 ;
  exo:patient_gender exo:gender_male .

那么您的映射应该是:

@prefix rr: <http://www.w3.org/ns/r2rml#>.
@prefix rml: <http://semweb.mmlab.be/ns/rml#>.
@prefix ql: <http://semweb.mmlab.be/ns/ql#>.
@prefix xsd: <http://www.w3.org/2001/XMLSchema#>.
@prefix exo: <http://example.org/ontology/>.
@prefix exr: <http://example.org/resource/>.

<#RecordMapping>
  rml:logicalSource [
    rml:source "/home/skralin/Desktop/results.json";
    rml:referenceFormulation ql:JSONPath;
    rml:iterator "$.results.[*]"
  ];

  rr:subjectMap [
    rr:template "http://example.org/resource/record_{record_id}";
    rr:class exo:Record 
  ];

  rr:predicateObjectMap [
    rr:predicate exo:patient_gender;
    rr:objectMap [
       rr:parentTriplesMap <#GenderMapping>
    ]
  ];

  rr:predicateObjectMap [
    rr:predicate exo:patient_age;
    rr:objectMap [
      rml:reference "demographics.age" ;
      rr:datatype xsd:integer
    ]
  ]. 

<#GenderMapping>
  rml:logicalSource [
    rml:source "/home/skralin/Desktop/results.json";
    rml:referenceFormulation ql:JSONPath;
    rml:iterator "$.results.[*].demographics.gender"
  ];

  rr:subjectMap [
    rr:template "http://example.org/resource/gender_{$}";
    rr:class exo:Gender
  ];

  rr:predicateObjectMap [
    rr:predicate rdfs:label;
    rr:objectMap [
      rml:reference "$"
    ]
  ].

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