Java - SAXParser ve XMLReader null öznitelikleri alır değer

Question

Bir XML dosyanız var ve SAX ürününü kullanmamalı. startElement() öğesinin sonuna kadar gider, çünkü öznitelik değerini almaya çalıştığımda bunlar boştur. Niye ya? Her şeyden

Önce bu yöntemi çağırın: yükü() İşte

public RealEstate load() { 
     RealEstate data = null; 
     try {  
      //Create a "parser factory" for creating SAX parsers 
      SAXParserFactory spfac = SAXParserFactory.newInstance(); 

      //Now use the parser factory to create a SAXParser object 
      SAXParser sp = spfac.newSAXParser(); 
      XMLReader xmlReader = sp.getXMLReader(); 

      //Create an instance of this class; it defines all the handler methods 
      SaxParserRealEstateHandler handler = new SaxParserRealEstateHandler(); 

      //assign our handler 
      xmlReader.setContentHandler(handler); 

      // Convert file to URL. 
      URL url = handler.fileToURL(new File(xmlFilename)); 

      // Parse file. 
      xmlReader.parse(url.toString()); 

      data = handler.getData(); 

     } catch (ParserConfigurationException ex) { 
      Logger.getLogger(RealStatePersistXML.class.getName()).log(Level.SEVERE, null, ex); 
     } 
     catch (SAXException ex) { 
      Logger.getLogger(RealStatePersistXML.class.getName()).log(Level.SEVERE, null, ex); 
     } 
     catch (IOException ex) { 
      Logger.getLogger(RealStatePersistXML.class.getName()).log(Level.SEVERE, null, ex); 
     } 
     return data; 
    } 

Ben yöntemleri startElement ve endElement var.

class SaxParserRealEstateHandler extends DefaultHandler 
    { 

     private String temp; 
     private RealEstate data; 
     private Estate estate; 
     private estateAddress address; 

     /** 
     * CONSTRUCTOR 
     */ 
     public SaxParserRealEstateHandler() 
     { 
     } 


     /** 
     * getData() 
     * This method gets the list of estates from RealEstate class. 
     * @return data list of states. Null in case of error or list not found. 
     */ 
     public RealEstate getData() 
     { 
     // RealEstate data = new RealEstate(); 
      // data.addEstate(estate); 
      // data.getEstates(); 
     // return data; 
     } 

     /* 
     * When the parser encounters plain text (not XML elements), 
     * it calls(this method, which accumulates them in a string buffer 
     */ 
     public void characters(char[] buffer, int start, int length) { 
      temp = new String(buffer, start, length); 
     } 


     /* 
     * Every time the parser encounters the beginning of a new element, 
     * it calls this method, which resets the string buffer 
     */ 
     public void startElement(String uri, String localName, String qName, Attributes attributes){ 

      switch (qName){  
       case"realState": 
        data = new RealEstate(); 
        break; 
       case"estate": 
        estate = new Estate(); 
        estate.setType(attributes.getValue("type")); 
        estate.setSurface(Double.parseDouble(attributes.getValue("surface"))); 
        //estate.setAddress(attributes.getValue("address")); 
        estate.setPrice(Integer.parseInt(attributes.getValue("price"))); 
        break;  
       case"address": 
        address = new estateAddress(); 
        address.setStreet(attributes.getValue("type")); 
        address.setNumber(Integer.parseInt(attributes.getValue("surface"))); 
        address.setFloor(Integer.parseInt(attributes.getValue("type"))); 
        address.setDoor(Integer.parseInt(attributes.getValue("surface"))); 
        break; 
       default: 
        break; 
      } 
     } 



    public void endElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { 

    switch (qName){ 
     case"estate": 
      data.getEstates().add(estate);//quant ha llegit la etiqueta (</estate>) l'agreguem 
      break; 
     case"surface": 
      double surface = Double.parseDouble(temp); 
      estate.setSurface(surface); 
      break; 
     case"price": 
      double price = Double.parseDouble(temp);//tractar tema errors del parseDouble! 
      estate.setPrice(price); 
      break;  
     case"address":      
      estate.setAddress(address); 
      break;  
     case"street": 
      address.setStreet(temp); 
      break; 
     case"number": 
      int number = Integer.parseInt(temp); 
      address.setNumber(number); 
      break; 
     case"floor": 
      address.setStreet(temp); 
      break; 
     case"door": 
      address.setStreet(temp); 
      break; 
     default: 
      break; 
    } 
} 



/** fileToURL() 
* Convenience method to convert a file to a url 
* @throws Error if malformed url exception is generated 
*/ 

    public URL fileToURL(File file) 
{ 
    String path = file.getAbsolutePath(); 
    String fSep = System.getProperty("file.separator"); 
    if (fSep != null && fSep.length() == 1) 
     path = path.replace(fSep.charAt(0), '/'); 
    if (path.length() > 0 && path.charAt(0) != '/') 
     path = '/' + path; 
    try 
    { 
     return new URL("file", null, path); 
    } 
    catch (java.net.MalformedURLException e) 
    { 
     throw new Error("Unexpected MalformedURLException");//no he pogut muntar una url com deu mana 
     //retornar null 
    } 
} 
    } 

XML kodu

<?xml version="1.0" encoding="UTF-8"?> 
<realState xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="realState.xsd"> 
    <estate> 
     <type>House</type> 
     <surface>250,0</surface> 
     <address> 
      <street>C/Tarragona</street> 
      <number>54</number> 
      <floor>2</floor> 
      <door>1</door> 
     </address> 
     <price>140000,0</price> 
    </estate> 
</realState> 

XSD kodu: http://pastebin.com/nzEDsdLg

Sınıflar RealEstate ve Emlak Tamam çalışıyoruz!

Teşekkür ederiz!

Answer 1

type, surface ve price<estate> elemanın nitelikleri değildir. Bunlar alt elementlerdir. Bir SAX ayrıştırıcı çok daha kolay ve çok benzerlik taşımaktadır Bir StAX ayrıştırıcı kullanarak

<estate type="House" surface="250,0" price="140000,0"> 
    <address> 
     <street>C/Tarragona</street> 
     <number>54</number> 
     <floor>2</floor> 
     <door>1</door> 
    </address> 
</estate> 

, bu yüzden onu kullanabilirsiniz önermek:

nitelikleri olmak için, size XML olurdu.