RDF4j .ttl 文件过滤器 IF 语句 [英] RDF4j .ttl file filter IF statement
问题描述
我在编译过程中遇到问题.你能帮忙找出问题吗?
I am having problem during compilation. Can you help to figure out the problem please?
`
public static void main(String[] args) throws IOException {
File dir = new File("C:data\\test");
String[] fileNames = dir.list();
FileWriter outFile = new FileWriter("out.ttl");
RDFWriter writer = org.eclipse.rdf4j.rio.Rio.createWriter(RDFFormat.TURTLE, outFile );
writer.startRDF();
for (String fileName : fileNames) {
System.out.println("Reading from " + fileName);
File f = new File(dir, fileName);
Model data = Rio.parse(new FileInputStream(f), "", RDFFormat.TURTLE);
for (Statement st: data) {
if ( "efrbroo:F22_Self-Contained_Expression" != null ) {
writer.handleStatement(st);
}
}
}
writer.endRDF();
}
`
这个问题的最初问题在这里:RDF4J 数据合并
The initial question with this problem is here: RDF4J data merge
推荐答案
您正在循环 Statement
对象,这些对象是 RDF 语句或三重"的 Java 表示.它有一个主题(可通过 Statement.getSubject()
获得)、一个谓词(Statement.getPredicate()
)和一个对象(Statement.getObject()代码>).请参阅https://rdf4j.eclipse.org/documentation/getting-started/更详细的介绍.
You are looping over Statement
objects, which are the Java representation of an RDF statement, or "triple". It has a subject (available via Statement.getSubject()
), a predicate (Statement.getPredicate()
) and an object (Statement.getObject()
). See https://rdf4j.eclipse.org/documentation/getting-started/ a more detailed introduction to this.
例如,如果您想删除所有以 IRI http://example.org/F22_Self-Contained_Expression
作为对象的三元组,您可以执行以下操作:
For example, if you wanted to remove all triples that had the IRI http://example.org/F22_Self-Contained_Expression
as their object, you'd do something like this:
IRI f22SelfContainedExpression = SimpleValueFactory.getInstance().createIRI("http://example.org/F22_Self-Contained_Expression");
...
if (!st.getObject().equals(f22SelfContainedExpression)) {
writer.handleStatement(st);
}
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