使用Jena 2.12.1加载模型时，RiotException [英] RiotException when loading a Model using Jena 2.12.1

问题描述

我创建了一个名为 RDFReader 的简单类，用于从DBpedia的URI加载模型:

I've created this simple class named RDFReader for loading a model from a URI from DBpedia:

import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.util.FileManager;

public class RDFReader {
    public static Model readFromURL(String URL){
      try{
         return (new FileManager()).loadModel(URL);
      }catch(Exception e){
         e.printStackTrace();
      }
      return null;  
     }

    public static void main(String[] args) {
      RDFReader.readFromURL("http://dbpedia.org/resource/Pacific_Rim_(film)");
    }   
}

我已使用 Jena v2.12.1，如以下pom.xml片段所示

I've used Jena v2.12.1 as shown in the following snippet of my pom.xml

    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>jena-core</artifactId>
        <version>2.12.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>jena-arq</artifactId>
        <version>2.12.1</version>
    </dependency>
    <dependency>

通过使用 Jena v2.12.1运行此代码，我有了下一个异常:

By running this code with Jena v2.12.1 I've got the next exception:

org.apache.jena.riot.RiotException: [line: 21, col: 17] Unknown char: –(8211;0x2013)
at org.apache.jena.riot.system.ErrorHandlerFactory$ErrorHandlerStd.fatal(ErrorHandlerFactory.java:136)
at org.apache.jena.riot.lang.LangEngine.raiseException(LangEngine.java:163)
at org.apache.jena.riot.lang.LangEngine.nextToken(LangEngine.java:106)
at org.apache.jena.riot.lang.LangTurtleBase.triples(LangTurtleBase.java:249)
at org.apache.jena.riot.lang.LangTurtleBase.triplesSameSubject(LangTurtleBase.java:191)
at org.apache.jena.riot.lang.LangTurtle.oneTopLevelElement(LangTurtle.java:44)
at org.apache.jena.riot.lang.LangTurtleBase.runParser(LangTurtleBase.java:90)
at org.apache.jena.riot.lang.LangBase.parse(LangBase.java:42)
at org.apache.jena.riot.RDFParserRegistry$ReaderRIOTLang.read(RDFParserRegistry.java:182)
at org.apache.jena.riot.RDFDataMgr.process(RDFDataMgr.java:906)
at org.apache.jena.riot.RDFDataMgr.parse(RDFDataMgr.java:687)
at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:210)
at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:183)
at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:121)
at org.apache.jena.riot.RDFDataMgr.read(RDFDataMgr.java:112)
at org.apache.jena.riot.adapters.RDFReaderRIOT.read(RDFReaderRIOT.java:77)
at com.hp.hpl.jena.rdf.model.impl.ModelCom.read(ModelCom.java:253)
at com.hp.hpl.jena.util.FileManager.readModelWorker(FileManager.java:377)
at com.hp.hpl.jena.util.FileManager.loadModelWorker(FileManager.java:308)
at com.hp.hpl.jena.util.FileManager.loadModel(FileManager.java:260)
at edu.polito.rdf.utils.RDFReader.readFromURL(RDFReader.java:12)
at edu.polito.rdf.utils.RDFReader.main(RDFReader.java:20)

但是使用 Jena v2.11.0可以运行代码，没有任何问题.所以我想知道:

However using Jena v2.11.0 the code runs without any problem. So I would like to know:

1. 为什么 Jena 的2.12.1版本会产生此错误?
2. 是否可以使用 Jena 的2.12.1版本而不是2.11.0来解决此问题?

1. Why does the 2.12.1 version of Jena produce this error?
2. Is it possible to solve this problem to use the 2.12.1 version of Jena instead of the 2.11.0?.

顺便说一句，我使用的是 eclipse Luna 4.4.1 和Java版本"1.8.0_11".

By the way, I'm using eclipse Luna 4.4.1 and java version "1.8.0_11".

推荐答案

问题是我试图访问资源 http://dbpedia.org/resource/Pacific_Rim_(film)，其中包含字符0x2013(Em-dash)，该字符在Turtle中当时不合法.

The problem is that I was trying to access to the resource http://dbpedia.org/resource/Pacific_Rim_(film) which contains a character 0x2013 (Em-dash) that is not legal at that point in Turtle.

这是两个问题的答案:

1. 我使用的是Jena 2.12.1，该应用了内容协商，并在RDF/XML之前列出了Turtle，因此发现DBpedia(使用Turtle)中的资源是错误的(如前所述).在2.11.0版中，它可以毫无问题地运行，因为该版本存在一个错误，使解析器不那么宽容.然后在2.12.1版中修复了该错误，因此读取具有非法字符的资源将启动RiotException.

1. I was using Jena 2.12.1 which applies content negotiation and lists Turtle before RDF/XML so it found that the resource in DBpedia (with Turtle) was wrong (as explained before). With version 2.11.0 it run without problems because that version had a bug that allowed the parser to be lenient. This bug was then fixed in version 2.12.1, so reading a resource with an illegal character launches the RiotException.

解决方案只是向DBpedia索取可通过

The solution was simply to ask DBpedia for the RDF/XML (alternatively N-triples) of the resource which can be accessed through http://dbpedia.org/data/Pacific_Rim_(film).rdf. The final code to get the RDF/XML from DBpedia is:

注意:按照@AndyS的建议，我使用了RDFDataMgr.loadModel(String URI) :

import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.util.FileManager;

public class RDFReader {
   public static Model readFromURL(String URL){
        return RDFDataMgr.loadModel(URL);
   }

   public static void main(String[] args) {
        Model model =      RDFReader.readFromURL("http://dbpedia.org/data/Pacific_Rim_(film).rdf");
     }
}

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