CODEWITHSUNDEEP
xmlvectorxstreamxml-deserialization
MiamiCane99
MiamiCane99

Reputation: 73

Read XML file into vector of objects using XStream

I'd like to use an XML file as a dictionary for an NLP project I'm working on. I currently have a "Words" class which is a vector of "Word" objects.

public class Words {

private Vector<Word> vect;

public Words(){
    vect = new Vector<Word>();
}

public void add(Word w){
    vect.add(w);
}

The "Word" class looks something like this:

public class Word {
private String name;
private String partOfSpeech;
private String category;
private String definition;
}

I have managed to write the "Words" vector to XML using XStream by using this code:

public class Writer {

public static void main(String[] args) {

    XStream xstream = new XStream();
    xstream.alias("words", Words.class);
    xstream.alias("word", Word.class);
    xstream.addImplicitCollection(Words.class, "vect");

    Words vect = new Words();
    vect.add(new Word("dog", "noun", "animal", "a domesticated  canid, Canis  familiaris,  bred  in  many  varieties"));
    vect.add(new Word("cat", "noun", "animal", "a small domesticated carnivore, Felis domestica or F. catus, bred in a number of varieties"));


    try {
        FileOutputStream fs = new FileOutputStream("c:/dictionary.xml");
        xstream.toXML(vect, fs);
    } catch (FileNotFoundException e1) {
        e1.printStackTrace();
    }
}
}

This all seems to work fine and gives me the following XML file:

<words>
   <word>
      <name>dog</name>
      <partOfSpeech>noun</partOfSpeech>
      <category>animal</category>
      <definition>a domesticated  canid, Canis  familiaris,  bred  in  many  varieties</definition>
   </word>
   <word>
      <name>cat</name>
      <partOfSpeech>noun</partOfSpeech>
      <category>animail</category>
      <definition>a small domesticated carnivore, Felis domestica or F. catus, bred in a number of varieties</definition>
   </word>
</words>

My question is how do I use XStream to read this XML file back into a vector of objects?

Upvotes: 1

Views: 1365

Answers (2)

Externer
Externer

Reputation: 1

Use http://www.java2s.com/Code/Jar/x/xpp3.htm for parsing. xstream automaticaly detects it. Then one Line: Vector g = (Vector) xstream.fromXML(String xml );

Upvotes: 0

MiamiCane99
MiamiCane99

Reputation: 73

I was able to read the file in using the following code:

public class Reader {
public static void main(String[] args) {

    XStream xstream = new XStream(new DomDriver());
    try {
    FileInputStream fis = new FileInputStream("c:/dictionary.xml");
    ObjectInputStream in = xstream.createObjectInputStream(fis);
    xstream.alias("word", Word.class);

    Word a = (Word)in.readObject();
    Word b = (Word)in.readObject();

    in.close();

    System.out.println(a.toString());
    System.out.println(b.toString());

    } catch (FileNotFoundException ex) {
        ex.printStackTrace();
    } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }       
}

}

Now, instead of saying: 

Word a = (Word)in.readObject();
Word b = (Word)in.readObject();

I'd like to read the objects into a vector by using a loop. My only problem now is how can I know how many objects are in the ObjectInputStream. It doesn't appear to have a method that tells me the number of objects or the size...

Upvotes: 1

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