XML 解析 Java DOM

Question

所以我需要解析一個有多項選擇題的 XML，這是一個示例問題：

所以我可以很容易地得到問題和正確答案的 id，但我似乎無法得到答案（選項）。 這是我正在使用的代碼：

            try {
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(inputFile);

        doc.getDocumentElement().normalize();
        System.out.println("Root element :" + doc.getDocumentElement().getNodeName());
        NodeList nList = doc.getElementsByTagName("Question");
        System.out.println("----------------------------");


        for (int temp = 0; temp < nList.getLength(); temp++) {
            Node nNode = nList.item(temp);
            //System.out.println("\nCurrent Element :" + nNode.getNodeName());

            if (nNode.getNodeType() == Node.ELEMENT_NODE) {
                Element QuestionElement = (Element) nNode;
                String Question = 
    QuestionElement.getElementsByTagName("text").item(0).getTextContent();
                int answerID = 0;
                try {
                    answerID = Integer.parseInt(QuestionElement.getAttribute("answerid"));
                }
                catch(NumberFormatException e) {
                    System.out.println("Error in parsing Answer ID value for:  " + Question);
                    throw e;
                }

                this.listofQuestions.add(new Question(Question,answerID));

            }
        }


    }
    catch(Exception e) {
        System.out.println("Error in parsing the XML file: " + filename);
        throw e;
    }

Answer 1

既然您無論如何都要將數據存儲在Question and Answer類中，為什么不讓 JAXB 為您進行解析呢？

@XmlRootElement(name = "QuestionBank")
class QuestionBank {
    @XmlElement(name = "Question")
    List<Question> questions;

    @Override
    public String toString() {
        return "QuestionBank" + this.questions;
    }
}

class Question {
    @XmlAttribute
    int id;

    @XmlElement
    String text;

    @XmlAttribute
    int answerid;

    @XmlElementWrapper(name = "answers")
    @XmlElement(name = "option")
    List<Answer> answers;

    @Override
    public String toString() {
        return "Question[id=" + this.id + ", text=" + this.text +
                      ", answerid=" + this.answerid + ", answers=" + this.answers + "]";
    }
}

class Answer {
    @XmlAttribute
    int id;

    @XmlValue
    String text;

    @Override
    public String toString() {
        return this.id + ": " + this.text;
    }
}

測試

QuestionBank questions = (QuestionBank) JAXBContext.newInstance(QuestionBank.class)
        .createUnmarshaller().unmarshal(new File("test.xml"));
System.out.println(questions);

輸出

QuestionBank[Question[id=1, text=Who invented the BALLPOINT PEN?, answerid=1, answers=[1: Bito Brothers, 2: Waterman Brothers, 3: Bicc Brothers, 4: Write Brothers]]]