java - 如何通过Jena API生成rdf集合？

Question

我有 RDF/XML 数据，如下所示:

<rdf:RDF> 
    <rdf:Description rdf:about="https://localhost/process/members/test">
        <process:user rdf:resource="https://localhost/users/test"/>
        <process:roleAssignments rdf:parseType="Collection">
            <rdf:Description rdf:about="https://localhost/process/role/ProductOwner">
                <process:roleUrl rdf:resource="https://localhost/role/ProductOwner"/>
            </rdf:Description>
            <rdf:Description rdf:about="https://localhost/process/role/TeamMember">
                <process:roleUrl rdf:resource="https://localhost/role/TeamMember"/>
            </rdf:Description>
        </process:roleAssignments>
    </rdf:Description>
</rdf:RDF>

不是很严格，但我只是想知道如何使用 Jena API 输出 rdf:Collection，如上面的示例。

Answer 1

令人困惑的是parsetype="collection"创建的是一个rdf列表，而不是一个集合。这可能会阻碍您的搜索。

你想要的是 RDFList您可以使用 number of methods in Model 创建。假设您已经拥有所需的大部分资源和属性(property)。该列表可以按如下方式创建:

// ... create model, resources, and properties as usual ...

// create the role assignments as you normally would
model.add(productOwner, roleUrl, productOwner);
model.add(teamMember, roleUrl, teamMember);

// Create a list containing the subjects of the role assignments in one go
RDFList list = model.createList(new RDFNode[] {productOwner, teamMember}));

// Add the list to the model
model.add(test, roleAssignments, list);

// ... now write the model out as rdf/xml or whatever you like ...

您还可以创建一个空列表并将每个项目添加到其中。