从本体实例中提取数据属性值

Question

我正在尝试显示我的本体实例的数据属性值。我为此目的使用耶拿。我的实例如下：

<!-- http://www.semanticweb.org/ontologies/2013/3/Ontology1365003423152.owl#Mailbomb -->

<NamedIndividual rdf:about="&Ontology1365003423152;Mailbomb">
    <rdf:type rdf:resource="&Ontology1365003423152;Attack"/>
    <Ontology1365003423152:HasService>smtp</Ontology1365003423152:HasService>
    <Ontology1365003423152:HasFlag>SF</Ontology1365003423152:HasFlag>
    <Ontology1365003423152:HasDuration>1</Ontology1365003423152:HasDuration>
    <Ontology1365003423152:hasSrcBytes>2599</Ontology1365003423152:hasSrcBytes>
    <Ontology1365003423152:HasType>Mailbomb</Ontology1365003423152:HasType>
    <Ontology1365003423152:HasProtocol>tcp</Ontology1365003423152:HasProtocol>
    <Ontology1365003423152:hasDestBytes>293</Ontology1365003423152:hasDestBytes>
</NamedIndividual>

<!-- http://www.semanticweb.org/ontologies/2013/3/Ontology1365003423152.owl#Smurf -->

<NamedIndividual rdf:about="&Ontology1365003423152;Smurf">
    <rdf:type rdf:resource="&Ontology1365003423152;Attack"/>
    <Ontology1365003423152:HasService>ecr_i</Ontology1365003423152:HasService>
    <Ontology1365003423152:HasProtocol>icmp</Ontology1365003423152:HasProtocol>
    <Ontology1365003423152:hasSrcBytes>1032</Ontology1365003423152:hasSrcBytes>
    <Ontology1365003423152:HasFlag>SF</Ontology1365003423152:HasFlag>
    <Ontology1365003423152:HasType>Smurf</Ontology1365003423152:HasType>
    <Ontology1365003423152:hasDestBytes>0</Ontology1365003423152:hasDestBytes>
    <Ontology1365003423152:HasDuration>0</Ontology1365003423152:HasDuration>
</NamedIndividual>

而我在 Java 中使用 Jena 的代码如下：

public static void main(String[] args) {
            String a[] =  new String [7];
            OntProperty p[] = new OntProperty [7];  
     OntModel inf = ModelFactory.createOntologyModel();
     InputStream in = FileManager.get().open(inputFileName);
     if (in == null) {
       throw new IllegalArgumentException("File: " + inputFileName + " not found");
     }
     inf.read(in, "");
     OntClass clas =inf.getOntClass("http://www.semanticweb.org/ontologies/2013/3/Ontology1365003423152.owl#Attack");
     p[0] = inf.getOntProperty("HasProtocol");
     p[1] = inf.getOntProperty("HasService");
     p[2] = inf.getOntProperty("HasDuration");
     p[3] = inf.getOntProperty("HasFlag");
     p[4] = inf.getOntProperty("hasSrcBytes");
     p[5] = inf.getOntProperty("hasDestBytes");
     p[6] = inf.getOntProperty("HasType");
     ExtendedIterator instances = clas.listInstances();
     Individual instance = null;
     while (instances.hasNext()) {
       instance = (Individual) instances.next();
       System.out.println(a[0] = instance.getPropertyValue(p[0]).toString());
       System.out.println(a[1] = instance.getPropertyValue(p[1]).toString());
       System.out.println(a[2] = instance.getPropertyValue(p[2]).toString());
       System.out.println(a[3] = instance.getPropertyValue(p[3]).toString());
       System.out.println(a[4] = instance.getPropertyValue(p[4]).toString());
       System.out.println(a[5] = instance.getPropertyValue(p[5]).toString());
       System.out.println(a[6] = instance.getPropertyValue(p[6]).toString());
     }
}

现在第一次打印只打印零，而第二次打印只打印 293（7 乘以 0，然后是 7 乘以 293）。我想我做错了什么，因为它正在为所有内容检索相同的值。我看到它的方式只是打印每个实例的最后一个数据属性值。

Answer 1

正如您需要在

中指定整个 IRI

inf.getOntClass("http://www.semanticweb.org/ontologies/2013/3/Ontology1365003423152.owl#Attack");

你需要在

中指定整个IRI

p[0] = inf.getOntProperty("HasProtocol");

由于可能没有带有 IRI 的 OntProperty HasProtocol，p[0]（以及其他）被设置为 null，并且在许多地方 Jena API 将 null 解释为通配符。所以

instance.getPropertyValue(p[0]).toString());

只是在模型中查询以instance 作为主语和任何谓词和任何宾语的三元组。 Jena 恰好每次都为每个 instance 返回相同的三元组。我猜这不是文件中提到的最后一个，而是 [instance, hasDestBytes, ...] 三元组，基于如何存储或索引三元组的一些工件。无论哪种方式，由于它只是通配符匹配的结果，因此行为可能没有精确定义。做这样的事情，你应该都准备好了：

String ns = "http://www.semanticweb.org/ontologies/2013/3/Ontology1365003423152.owl#";
OntClass clas = inf.getOntClass(ns + "Attack");
p[0] = inf.getOntProperty(ns + "HasProtocol");
p[1] = inf.getOntProperty(ns + "HasService");