如何在Java中將JSON數組轉換為RDF？

Question

我想將JSON（不是JSON-LD）數組轉換為Java中的RDF。 我在論壇上看到過類似的帖子，但沒有確切的答案。 JSON數組包含對象和數組，例如：

{
   "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 }
      }
   ]
}

有任何想法嗎？ 感謝名單！

Answer 1

我建議您不要對轉換進行硬編碼。

對於RDBMS源（順便說一句，為什么不使用它們），有W3C標准化的R2RML （ r2rml ）。
對於JSON和XML源，有RML ，是R2RML的非官方擴展。

RML Mapper是RML的Java實現：

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

通常，應將rml:iterator "$.results.[*]"放在rml:logicalSource部分中，以遍歷數組元素。 確切的答案取決於您要使用的詞匯表以及要實現的數據模型。

假設您需要這樣的東西：

@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 .

然后，您的映射應為：

@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 "$"
    ]
  ].

Answer 2

您可以定義適當的@context並使用任何JSON-LD轉換器創建任何RDF序列化。 在這里和這里找到Java示例 。

例

{
"@context":{
"results":{
  "@id":"info:stack/49365220/results",
  "@container":"@list"
},
"record_id":{
  "@id":"info:stack/49365220/record_id"
}, 
"gender":{
  "@id":"info:stack/49365220/gender"
}, 
"age":{
  "@id":"info:stack/49365220/age"
},
"demographics":{
  "@id":"info:stack/49365220/demographics"
}
},
"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 }
  }
   ]
}

將其放到Json-Ld Playground （或任何其他RDF工具 ）中時，您可以生成如下內容：

序列化為N-TRIPLE

_:b0 <info:stack/49365220/results> _:b13 .
_:b1 <info:stack/49365220/demographics> _:b2 .
_:b1 <info:stack/49365220/record_id> "3d87f4df-f17e-4632-9449" .
_:b10 <info:stack/49365220/age> "40"^^<http://www.w3.org/2001/XMLSchema#integer> .
_:b10 <info:stack/49365220/gender> "female" .
_:b11 <info:stack/49365220/demographics> _:b12 .
_:b11 <info:stack/49365220/record_id> "f3ccfdf6-231e-4a3e-bee0" .
_:b12 <info:stack/49365220/age> "118"^^<http://www.w3.org/2001/XMLSchema#integer> .
_:b12 <info:stack/49365220/gender> "male" .
_:b13 <http://www.w3.org/1999/02/22-rdf-syntax-ns#first> _:b1 .
_:b13 <http://www.w3.org/1999/02/22-rdf-syntax-ns#rest> _:b14 .
_:b14 <http://www.w3.org/1999/02/22-rdf-syntax-ns#first> _:b3 .
_:b14 <http://www.w3.org/1999/02/22-rdf-syntax-ns#rest> _:b15 .
_:b15 <http://www.w3.org/1999/02/22-rdf-syntax-ns#first> _:b5 .
_:b15 <http://www.w3.org/1999/02/22-rdf-syntax-ns#rest> _:b16 .
_:b16 <http://www.w3.org/1999/02/22-rdf-syntax-ns#first> _:b7 .
_:b16 <http://www.w3.org/1999/02/22-rdf-syntax-ns#rest> _:b17 .
_:b17 <http://www.w3.org/1999/02/22-rdf-syntax-ns#first> _:b9 .
_:b17 <http://www.w3.org/1999/02/22-rdf-syntax-ns#rest> _:b18 .
_:b18 <http://www.w3.org/1999/02/22-rdf-syntax-ns#first> _:b11 .
_:b18 <http://www.w3.org/1999/02/22-rdf-syntax-ns#rest> <http://www.w3.org/1999/02/22-rdf-syntax-ns#nil> .
_:b2 <info:stack/49365220/age> "20"^^<http://www.w3.org/2001/XMLSchema#integer> .
_:b2 <info:stack/49365220/gender> "female" .
_:b3 <info:stack/49365220/demographics> _:b4 .
_:b3 <info:stack/49365220/record_id> "ec5ca92d-865a-431f-9984" .
_:b4 <info:stack/49365220/age> "118"^^<http://www.w3.org/2001/XMLSchema#integer> .
_:b4 <info:stack/49365220/gender> "male" .
_:b5 <info:stack/49365220/demographics> _:b6 .
_:b5 <info:stack/49365220/record_id> "0a79ecf0-83d8-4148-9054" .
_:b6 <info:stack/49365220/age> "118"^^<http://www.w3.org/2001/XMLSchema#integer> .
_:b6 <info:stack/49365220/gender> "female" .
_:b7 <info:stack/49365220/demographics> _:b8 .
_:b7 <info:stack/49365220/record_id> "229276f8-1893-480b-b6e7" .
_:b8 <info:stack/49365220/age> "35"^^<http://www.w3.org/2001/XMLSchema#integer> .
_:b8 <info:stack/49365220/gender> "female" .
_:b9 <info:stack/49365220/demographics> _:b10 .
_:b9 <info:stack/49365220/record_id> "0574cc3b-fb9c-495f-851c" .