如何使用Java rdf4j将RDF转换为漂亮的嵌套JSON

如何使用Java rdf4j将RDF转换为漂亮的嵌套JSON

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);        }    }        public static String getPrettyJsonLdString(InputStream in, RDFFormat format) {        return getPrettyJsonLdString(     readRdfToString(in, format, RDFFormat.JSONLD, ""));    }        public static String getPrettyJsonLdString(Collection<Statement> 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<String, Object> removeGraphArray(Map<String, Object> framedJson) {        List<Map<String,Object>> graph = (List<Map<String, Object>>) framedJson.get("@graph");        return graph.get(0);    }    private static Map<String, Object> getframedJson(Object json) {        try { return JsonLdProcessor.frame(json, getframe(), new JsonLdOptions());        } catch (Exception e) { throw new RuntimeException(e);        }    }    private static Map<String, Object> getframe() {        Map<String, Object> 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<Statement> 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<Statement> myGraph = null;        myGraph = readRdfToGraph(in, inf, baseUrl);        return graphToString(myGraph, outf);    }    public static String graphToString(Collection<Statement> 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();    }}

版画

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

带绒球

<dependency>        <groupId>org.eclipse.rdf4j</groupId>        <artifactId>rdf4j-runtime</artifactId>        <version>2.2</version>        <type>pom</type>    </dependency><dependency>        <groupId>com.github.jsonld-java</groupId>        <artifactId>jsonld-java</artifactId>        <version>0.10.0</version></dependency>