如何使用java rdf4j将RDF转换为漂亮的嵌套JSON

我有一个简单的RDF文件，并希望将其转换为漂亮的嵌套JSON。

:b0 a  ;  "Semantic Web Primer (First Edition)" ;  _:b1 ;  "Linked Data Tools" . _:b1 a  ;  "2.95" ;  "USD" . 

应该成为

 { "type" : "Book", "name" : "Semantic Web Primer (First Edition)", "offers" : { "type" : "Offer", "price" : "2.95", "priceCurrency" : "USD" }, "publisher" : "Linked Data Tools" } 

Answer 1

使用框架

 import java.io.ByteArrayInputStream; import java.io.InputStream; import java.io.StringWriter; import java.util.Collection; import java.util.HashMap; import java.util.List; import java.util.Map; import org.eclipse.rdf4j.model.Statement; import org.eclipse.rdf4j.rio.RDFFormat; import org.eclipse.rdf4j.rio.RDFHandlerException; import org.eclipse.rdf4j.rio.RDFParser; import org.eclipse.rdf4j.rio.RDFWriter; import org.eclipse.rdf4j.rio.Rio; import org.eclipse.rdf4j.rio.helpers.StatementCollector; import org.junit.Test; import com.github.jsonldjava.core.JsonLdOptions; import com.github.jsonldjava.core.JsonLdProcessor; import com.github.jsonldjava.utils.JsonUtils; import com.google.common.base.Charsets; public class HowToConvertRdfToJson { @Test public void convertRdfToPrettyJson(){ try(InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream("book.ttl")){ System.out.println(getPrettyJsonLdString(in,RDFFormat.TURTLE)); }catch(Exception e){ throw new RuntimeException(e); } } /** * @param in Input stream with rdf data * @param format format of the rdf data * @return a pretty JSON document as String */ public static String getPrettyJsonLdString(InputStream in, RDFFormat format) { return getPrettyJsonLdString( readRdfToString(in, format, RDFFormat.JSONLD, "")); } /** * @param statements rdf statements collected * @return a pretty JSON document as String */ public static String getPrettyJsonLdString(Collection statements) { return getPrettyJsonLdString( graphToString(statements, RDFFormat.JSONLD)); } private static String getPrettyJsonLdString(String rdfGraphAsJson) { try { //@formatter:off return JsonUtils .toPrettyString( removeGraphArray( getFramedJson( createJsonObject( rdfGraphAsJson)))); //@formatter:on } catch (Exception e) { throw new RuntimeException(e); } } private static Map removeGraphArray(Map framedJson) { List> graph = (List>) framedJson.get("@graph"); return graph.get(0); } private static Map getFramedJson(Object json) { try { return JsonLdProcessor.frame(json, getFrame(), new JsonLdOptions()); } catch (Exception e) { throw new RuntimeException(e); } } private static Map getFrame() { Map context = new HashMap<>(); context.put("@context", "http://schema.org/"); return context; } private static Object createJsonObject(String ld) { try (InputStream inputStream = new ByteArrayInputStream(ld.getBytes(Charsets.UTF_8))) { Object jsonObject = JsonUtils.fromInputStream(inputStream); return jsonObject; } catch (Exception e) { throw new RuntimeException(e); } } public static Collection readRdfToGraph( final InputStream inputStream, final RDFFormat inf, final String baseUrl) { try { final RDFParser rdfParser = Rio.createParser(inf); final StatementCollector collector = new StatementCollector(); rdfParser.setRDFHandler(collector); rdfParser.parse(inputStream, baseUrl); return collector.getStatements(); } catch (final Exception e) { throw new RuntimeException(e); } } public static String readRdfToString(InputStream in, RDFFormat inf, RDFFormat outf, String baseUrl) { Collection myGraph = null; myGraph = readRdfToGraph(in, inf, baseUrl); return graphToString(myGraph, outf); } public static String graphToString(Collection myGraph, RDFFormat outf) { StringWriter out = new StringWriter(); RDFWriter writer = Rio.createWriter(outf, out); try { writer.startRDF(); for (Statement st : myGraph) { writer.handleStatement(st); } writer.endRDF(); } catch (RDFHandlerException e) { throw new RuntimeException(e); } return out.getBuffer().toString(); } } 

打印

 { "id" : "_:b0", "type" : "Book", "name" : "Semantic Web Primer (First Edition)", "offers" : { "id" : "_:b1", "type" : "Offer", "price" : "2.95", "priceCurrency" : "USD" }, "publisher" : "Linked Data Tools" } 

随着pom

  org.eclipse.rdf4j rdf4j-runtime 2.2 pom   com.github.jsonld-java jsonld-java 0.10.0