在java中使用jena API顯示RDF

Question

我在StoryModel中創建了幾個方法。如果代碼中有任何錯誤，我真的很感謝修正。

public class StoryModel { 

    String dbName = "DB3"; 
    String sns = "http://somebook/SemBook#"; 
    String ns; 
    Dataset ds; 
    OntModel om; 

    // create model and connect to database 
    public StoryModel(String storyName){ 

     ns = sns + storyName; 
     ds = TDBFactory.createDataset(dbName); 
     om = ModelFactory.createOntologyModel(); 

    } 

    // create classes in model 
    public void initModel() { 

     om.createClass(ns + "Person"); 
     om.createClass(ns + "Event"); 
     om.createClass(ns + "Place"); 
     om.createClass(ns + "Time"); 
     om.createClass(ns + "Object"); 
     saveModel(); 
    } 

    //Read & write in database 
    //Display it 
    public void saveModel() { 

     ds.begin(ReadWrite.WRITE); 
     om.write(System.out, "RDF/XML-ABBREV"); 

    } 

    // Create resource to class in model 
    public Resource createResource(String resourceName, String clsName) { 

     OntResource resource = om.createOntResource(ns + resourceName); 
     String ruri = ns + resource; 
     OntClass clsuri = om.getOntClass(ns + clsName); 

     Individual i = om.createIndividual(ruri, clsuri); 

     return i; 

    } 

    /* 
    * Return an RDF resource object given the URI of the resource as a string. The 
    * URI can be represented in full, or as a "prefix:localName". 
    * @param resourceName The full URI of the resource 
    * @return An RDF resource object 
    */ 

    public Resource stringToResource(String resourceName) { 

     String resourceURI = om.expandPrefix(resourceName); 

     return om.getResource(resourceURI); 

    } 

    // Delete the resource 
    public void deleteResource(String resourceName) { 

     try { 
      OntResource resource = om.getOntResource(ns + resourceName); 

      if (resource != null) 
      { 
       resource.remove(); 
      } 
      else { 
       System.out.println("Resource not present"); 
      } 
     } 
     catch (Exception e) { }   
    } 
} 

在SemBookMain我創建了一個模型，並初始化類都使用與StoryModel創建的方法與資源，並顯示它

public class SemBookMain { 

    public static void main(String[] args) { 

     // create and initialize a model 
     StoryModel sm = new StoryModel("alice"); 
     //sm.saveModel(); 
     sm.initModel(); 

     // add resources 
     String clsName = "Person"; 
     String[] ar = {"Alice", "Peter", "Ben", "Robin"}; 

     for (String r : ar) { 

      Resource res = sm.createResource(r, clsName); 

     } 
     sm.saveModel(); 

    } 

} 

我真的很抱歉，我加輸出如下，請看到的評論我的評論。

我不明白關於錯誤1 & 2以及爲什麼資源不顯示。有一些我失蹤，但無法弄清楚。

Answer 1

ds.begin(ReadWrite.WRITE);但沒有ds.commit

initModel調用saveModel，然後你再打電話過來saveModel。

按照代碼模式爲：

http://jena.apache.org/documentation/tdb/tdb_transactions.html#write-transactions