java - 使用 SAX 解析 XML

Question

嗨，我无法弄清楚如何读取我的 XML 文件。

我正在使用 Sax，但我似乎无法让 SAX 读取“ansArray”的子节点。我不确定我的 XML 格式是否错误，任何帮助都会很棒。

注意XML 文档是通过使用 XStream 保存的，这就是为什么“AnsArray”有 4 个字符串项。

XML 文档:

<?xml version="1.0" encoding="utf-8" ?>
  <questionList>
    <Question>
      <id>-1</id>
      <question>&quot;Who Was Sleepless In Seattle With Meg Ryan?&quot;</question>
      <ansArray>
        <string>&quot;Bruce Willis&quot;</string>
        <string>&quot;Arnie Schwarzenegger&quot;</string>
        <string>&quot;Joe Pesci&quot;</string>
        <string>&quot;Tom Hanks&quot;</string>
      </ansArray>
      <correctAns>4</correctAns>
      <iDifficulty>2</iDifficulty>
    </Question>
    <Question>
      <id>-1</id>
      <question>&quot;who was the Terminator?&quot;</question>
      <ansArray>
        <string>&quot;John Travolta&quot;</string>
        <string>&quot;Stevan Segal&quot;</string>
        <string>&quot;Arnie Schwarzenegger&quot;</string>
        <string>&quot;Al Pacino&quot;</string>
      </ansArray>
      <correctAns>3</correctAns>
      <iDifficulty>3</iDifficulty>
    </Question>
 </questionList>

在上面的 XML 文件中，我可以读取除 ansArray 的子节点之外的所有内容，即

  <ansArray>
    <string>&quot;John Travolta&quot;</string>
    <string>&quot;Stevan Segal&quot;</string>
    <string>&quot;Arnie Schwarzenegger&quot;</string>
    <string>&quot;Al Pacino&quot;</string>
  </ansArray>

SAX XML 代码:

import java.util.ArrayList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class SAX_XMLReader extends DefaultHandler {

    boolean currentElement = false;
    String currentValue = "";

    static Question question;
    static ArrayList<Question> questionList=new ArrayList<Question>();

    ArrayList<String> sAnswers=new ArrayList<String>(4);   

    public static ArrayList<Question> getquestionList() {
        return questionList;
    }

    @Override
    public void startElement(String uri, String localName, String qName,
            Attributes atts) throws SAXException {

        currentElement = true;

        //System.out.println("qName = "+qName );

        if (qName.equals("questionList")) {
            questionList = new ArrayList<Question>();
        } else if (qName.equals("Question")) {
            question = new Question();
        } //how to handle the answer string array
        else if (qName.equalsIgnoreCase("ansArray")) { 
              //??
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName)
            throws SAXException {

        currentElement = false;

        //System.out.println("qName = "+qName );

        if(qName.equals("question")) 
        {
            question.setQuestion(currentValue.trim());
            //System.out.println("Q: "+currentValue.trim());
        } 
        else if (qName.equalsIgnoreCase("correctAns")) {
            question.setCorrectAns(Integer.parseInt(currentValue.trim()));            
        } 
        else if (qName.equalsIgnoreCase("iDifficulty")) {
            question.setiDifficulty(Integer.parseInt(currentValue.trim()));        
        }    
        else if (qName.equalsIgnoreCase("ansArray")) {
            //??
        }             

        else if (qName.equals("Question")) {
            questionList.add(question);
        }

        currentValue = "";            

    }

    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {

        if (currentElement) {
            currentValue = currentValue + new String(ch, start, length);
        }

    }

}

问题类别:

import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.annotations.XStreamImplicit;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

//change string array to list

public class Question implements Serializable{

    private int id=-1;        
    private String question="";        
    //private String[] ansArray = new String[4];        
        ArrayList<String> sAnswers=new ArrayList<String>(4);     
    private int correctAns=-1;
    private int iDifficulty=-1;


    public Question(){
            //sAnswers=new ArrayList<String>();
            for(int x=0;x<4;x++){
                sAnswers.add("default answer "+x);
            }
    }

    //testing contructor
        public Question(int id,String sQuestion){

                this.id=id;
        this.question =sQuestion;
    }


    public Question(int id,String sQuestion,String sAns1){

                this.id=id;
        this.question =sQuestion;
                this.sAnswers.add(sAns1);

        //this.ansArray[0]=sAns1;
    }

    public Question(String sQuestion,String sAns1,String sAns2,String sAns3,String sAns4,int iCorrectAns){

                this.question =sQuestion;
        this.sAnswers.add(sAns1);
                this.sAnswers.add(sAns2);
                this.sAnswers.add(sAns3);
                this.sAnswers.add(sAns4);
        this.correctAns =iCorrectAns;
    }

    //constuctor with difficuly int(1-15)
    public Question(String sQuestion,String sAns1,String sAns2,String sAns3,String sAns4,int iCorrectAns,int iDifficulty){

                this.question =sQuestion;
        this.sAnswers.add(sAns1);
                this.sAnswers.add(sAns2);
                this.sAnswers.add(sAns3);
                this.sAnswers.add(sAns4);
        this.correctAns =iCorrectAns;
        this.iDifficulty=iDifficulty;
    }

    //constuctor with difficuly int(1-15)
    public Question(int id,String sQuestion,String sAns1,String sAns2,String sAns3,String sAns4,int iCorrectAns,int iDifficulty){

                this.id=id;
        this.question =sQuestion;
        this.sAnswers.add(sAns1);
                this.sAnswers.add(sAns2);
                this.sAnswers.add(sAns3);
                this.sAnswers.add(sAns4);
        this.correctAns =iCorrectAns;
        this.iDifficulty=iDifficulty;
    }



    public int getiDifficulty() {
        return iDifficulty;
    }

    public void setiDifficulty(int iDifficulty) {
        this.iDifficulty = iDifficulty;
    }

    public int getID() {
        return id;
    }


    public void setID(int id) {
        this.id = id;
    }


    public String getQuestion() {
        return question;
    }


    public void setQuestion(String question) {
        this.question = question;
    }


    public String getAnswer(int i){
            return sAnswers.get(i);

    }


    public void setAnswer(int i,String answer){     
            sAnswers.add(answer);
    }


    //get the correct answer as a string
    public String sGetCorrectAnswer(){
        return sAnswers.get(correctAns);
    }


    public String getAnswersList()
    {
        String s="\nA) " + sAnswers.get(0) + 
                 "\nB) " + sAnswers.get(1) +
                 "\nC) " + sAnswers.get(2) +
                 "\nD) " + sAnswers.get(3);
        return s;
    }


    public int getiCorrectAns() {
        return correctAns;
    }
    public void setCorrectAns(int correctAns) {
        this.correctAns = correctAns;
    }


        @Override
    public String toString(){

        String log ="\n\nQuestion by ID" +
                "\n\nId: "+this.getID()+
                "\nQuestion: " + this.getQuestion() + 
                " \nAns1: " + this.getAnswer(0) +
                " \nAns2: " + this.getAnswer(1) +
                " \nAns3: " + this.getAnswer(2) +
                " \nAns4: " + this.getAnswer(3) +
                " \nCorrectAns: " + this.getiCorrectAns()+
                " \nDifficulty: " + this.getiDifficulty()
                ; 
        return log;
    }



}

Answer 1

每次找到 xml-start-tag 时都会调用

startElement()。这意味着它适用于您示例中的以下元素(qname):

• 问题列表
• 问题
• ID
• 问题
• ansArray
• 字符串
• 字符串
• 字符串
• 字符串
• 正确答案
• i难度
• 问题
• ID
• 问题
• ansArray
• 字符串
• 字符串
• 字符串
• 字符串
• 正确答案
• i难度

这意味着您必须自己管理 xml 数据中的位置(级别、元素树)。